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with analysis of gw190521 potentially indicating the existence of an eccentric black hole binary, the idea that active galactic nuclei (agn) are the birthplaces for binary black holes (bbhs) has picked up a lot of steam in recent months. an accretion disk of gas circling around the super massive black hole (smbh), agn disks are potential hosts to many black holes. sbhs in the agn are either pulled in, through gas torques, from the surrounding nuclear stellar cluster, or are simply born in the disk through in-situ star formation and evolution. playing host to these bhs, the environment of the agn disk can form bbhs through both dynamical and gaseous processes. our study sheds new light on how gaseous dynamical friction, the slowing of bodies in a medium by the gravitational pull of their wakes, can form bound sbh binaries from two single, close approach, sbhs. performing 2d 3-body integrations with rebound, we find that gaseous dynamical friction not only has the ability to form bbhs but it is quite good at it, being able to capture close approach black holes on a range of impact parameters, and in a range of different astrophysical systems. we discover that, unlike previous prescriptions, high levels of dynamical friction (equivalently over-dense gas) can actually hinder binary formation. we determine characteristics of the gas-captured binaries, reporting general trends in eccentricity, semi-major axis, direction of rotation, precession, and more across astrophysical parameters. we provide an analytic formula that determines the strength of dynamical friction in any astrophysical system and subsequently provide numerical limits to such formula, dictating when and where binaries form. our work not only provides a strong case for the importance of gaseous capture as a method for bbh formation in agn, but it also yields a detailed analytic formula that will provide much aid to population synthesis projects in their study of intermediate mass black hole growth, updating older, and not entirely accurate, semi-analytic models. in future work we hope to further study the implications our newly powerful dynamical friction has on the picture of agn as source for gw events and bbh mergers. | how to capture black holes: dynamical friction as a binary formation mechanism |
we present the first complete version of the new galaxy population synthesis model: galmod. the model aims to generate synthetic mock catalogs of visible portions of the milky way (mw) galaxy, m31, or any other local group galaxy. to describe a galaxy, we model it a sum of discrete stellar populations, namely bulge, disk, and halo. each disk population is itself the sum of subpopulations: spiral arms, thin disk, and thick disk. we define all these components by their density profile scale parameters. the galaxy potential is computed from these density profiles and used to generate the kinematics of the stellar populations. the same density profiles are used to define the observed color-magnitude diagrams in the field of view from an arbitrary solar location. galmod, first introduced by pasetto et al. (2016), has been completed with a new asymmetric bulge stellar population representing a bar and described by applying the density wave theory for bar instability to the modeled galaxy very central regions. new photometric systems have been included and made available online to cover sdss, gaia, 2mass, hst and other photometric systems. the extinction model has been updated accordingly to account for the new photometric system passbands. the model has free web page access and tutorial at <a href='www.galmod.org'>www.galmod.org</a>. | the galactic synthesis population model galmod |
in this tribute to margherita hack i will consider her work in connection to the problem of the light elements li, be b and d and with a brief overview of their current state. the title itself is taken from a review she wrote in 1965 when the origin of these element was quite mysterious. seeking a li source she found an excess of li in magnetic stars, which was a first evidence of a non thermal synthesis of this element. li in ap stars was a topic to which she returned in the last years of her scientific life. d comes all form the big bang. it is the best measured primordial element and the baryometer of choice. be and b are made by spallation processes in the interstellar but mainly close to sne. 7li is the most problematic one. there is a striking mismatch between the primordial prediction and what measured which has been standing since more than two decades. 7li has multiple sources but the one making most of it is still missing. however, the recent detection of 7be in the outburst spectra of novae makes them the most probable source. | the problem of lithium and the other light elements deuterium, beryllium and boron |
we build a theoretical picture of how the light from galaxies evolves across cosmic time. in particular, we predict the evolution of the galaxy spectral energy distribution (sed) by carefully integrating the star formation and metal enrichment histories of semi-analytic model (sam) galaxies and combining these with stellar population synthesis models which we call mentari. our sam combines prescriptions to model the interplay between gas accretion, star formation, feedback process, and chemical enrichment in galaxy evolution. from this, the sed of any simulated galaxy at any point in its history can be constructed and compared with telescope data to reverse engineer the various physical processes that may have led to a particular set of observations. the synthetic seds of millions of simulated galaxies from mentari can cover wavelengths from the far uv to infrared, and thus can tell a near complete story of the history of galaxy evolution. | mentari: a pipeline to model the galaxy sed using semi analytic models |
using a hybrid binary population synthesis approach, we modelled the formation and evolution of populations of accreting wds for differing star formation histories. we found that the delay time distribution of sne ia in the single degenerate scenario is inconsistent with observations. additionally, we found that our predicted x-ray and uv emission of populations of accreting wds are consistent with the x-ray luminosities of early-type galaxies observed by chandra and the heii 4686å/h\beta line ratio measured in stacked sdss spectra of passively evolving galaxies. moreover, we found that the majority of current novae in elliptical-like galaxies have low-mass wds, long decay times, long recurrence periods and are relatively faint. in contrast, the majority of current novae in spiral-like galaxies have massive wds, short decay times, short recurrence periods and are relatively bright. our predicted distribution of mass-loss timescales in an m31-like galaxy is consistent with observations for andromeda. | populations of accreting white dwarfs |
we review the measurements of magnetic fields of oba stars. based on these data we confirm that magnetic fields are distributed according to a lognormal law with a mean log(b)=-0.5 (b in kg) with a standard deviation sigma=0.5. the shape of the magnetic field distribution is similar to that for neutron stars. this finding is in favor of the hypothesis that the magnetic field of a neutron star is determined mainly by the magnetic field of its predecessor, the massive ob star. further, we model the evolution of an ensemble of magnetic massive stars in the galaxy. we use our own population synthesis code to obtain the distribution of stellar radii, ages, masses, temperatures, effective magnetic fields and magnetic fluxes from the pre-main sequence (pms) via zero age main sequence (zams) up to the terminal age main sequence (tams) stages. a comparison of the obtained in our model magnetic field distribution (mfd) with that obtained from the recent measurements of the stellar magnetic field allows us to conclude that the evolution of magnetic fields of massive stars is slow if not absent. the shape of the real mfd shows no indications of the magnetic desert proposed previously. based on this finding we argue that the observed fraction of magnetic stars is determined by physical conditions at the pms stage of stellar evolution. | statistics of magnetic field measurements and evolution of magnetic field of oba stars |
the recent detection of gravitational waves has proven the existence of massive stellar black hole binaries (bbhs), but the formation channels of bbhs are still an open question. here, we investigate the demography of bbhs by using our new population-synthesis code mobse. mobse is an updated version of the widely used binary population-synthesis code bse (hurley et al. 2000, hurley et al. 2002) and includes the key ingredients to determine the fate of massive stars: up-to-date stellar wind prescriptions and supernova models. with mobse, we form bbhs with total mass up to $\sim{}120$ m$_\odot$ at low metallicity, but only systems with total mass up to $\sim{}80$ m$_\odot$ merge in less than a hubble time. our results show that only massive metal-poor stars ($z\lesssim 0.002$) can be the progenitors of gravitational wave events like gw150914. moreover, we predict that merging bbhs form much more efficiently from metal-poor than from metal-rich stars. | unravelling the progenitors of merging black hole binaries |
considering as many as 70% of massive stars interact with a binary companion (sana et al. 2012, 2014), we created a new model of the optical nebular emission of hii regions by combining the results of the binary population and spectral synthesis (bpass, eldridge, stanway et al. 2017) code with the photoionization code (cloudy). this is discussed more in detail in xiao et al. 2018. then we use this model to explore a variety of emission-line diagnostics of ccsn host hii regions from the pmas/ppak integral-field supernova hosts compilation (pisco, galbany et al. 2018). we determine the age, metallicity and gas parameters for h ii regions associated with ccsne, contrasting the above variables to distribution type ii and type ibc sne. we find their nebular emission and ccsn progenitor types are largely determined by past and ongoing binary interactions, for example mass loss, mass gain and stellar mergers. however we note these two types sne have little preference in their host environment metallicity measured by oxygen abundance or in progenitor initial mass, except that at lower metallicities supernovae are more likely to be of type ii. the bpass and nebular emission models are available from http://bpass.auckland.ac.nz and http://warwick.ac.uk/bpass. | emission-line diagnostics of core-collapse supernova host hii regions including interacting binary population |
the study of the luminosity contribution from thermally pulsing asymptotic giant branch (tp-agb) stars to the stellar populations of galaxies is crucial to determine their physical parameters (e.g., stellar mass and age). we use a sample of 84 nearby disk galaxies to explore diverse stellar population synthesis models with different luminosity contributions from tp-agb stars. we fit the models to optical and near-infrared (nir) photometry, on a pixel-by-pixel basis. the statistics of the fits show a preference for a low-luminosity contribution (i.e., high mass-to-light ratio in the nir) from tp-agb stars. nevertheless, for 30%-40% of the pixels in our sample a high-luminosity contribution (hence low mass-to-light ratio in the nir) from tp-agb stars is favored. according to our findings, the mean tp-agb star luminosity contribution in nearby disk galaxies may vary with hubble type. this may be a consequence of the variation of the tp-agb mass-loss rate with metallicity, if metal-poor stars begin losing mass earlier than metal-rich stars, because of a pre-dust wind that precedes the dust-driven wind. | on the thermally pulsing asymptotic giant branch contribution to the light of nearby disk galaxies |
we estimate the stellar mass for a sample of low surface brightness galaxies (lsbgs) by fitting their multiband spectral energy distributions (seds) to the stellar population synthesis (sps) model. the derived stellar masses (log m*/msun) span from 7.1 to 11.1, with a mean of log m*/msun=8.5, which is lower than that for normal galaxies. the stellar mass-to-light ratio (m/l) in each band varies little with absolute magnitude, but increases with higher m*. this trend of m/l with m* is even stronger in bluer bands. in addition, the m/l for our lsbgs slightly declines from the r band to the longer wavelength bands. the log m/l_j (j=g,r,i,and z) have relatively tight relations with optical colors of g-r and g-i. compared with several representative m/l-color relations (mlcrs) from literature, our mlcrs based on lsbg data are consistently among those literature mlcrs previously defined on diverse galaxy samples, and the existing minor differences between the mlcrs are more caused by the differences in the sed model ingredients including initial mass function, star formation history, and stellar population model, and the line fitting techniques, galaxy samples, and photometric zero-point as well, rather than the galaxy surface brightness itself which distinguishes lsbgs from hsbgs. our lsbgs would be very likely to follow those representative mlcrs previously defined on diverse galaxy populations, if those main ingredients were taken into account. | stellar mass and stellar mass-to-light ratio-color relations for low surface brightness galaxies |
in this work, we study the optical properties of 58 css/gps radio sources selected from the literature in order to determine the impact of the radio-jet in the circumnuclear environment of these objects. we obtained optical spectra for all sources from sdss-dr12 and performed a stellar population synthesis using the starlight code. our results indicate that the sample is dominated by intermediate to old stellar populations and there is no strong correlation between optical and radio properties of these sources. | optical properties of css/gps sources |
hot subdwarf b stars are extreme horizontal-branch core-helium burning stars having masses of about $0.5 \, \mathrm{m}_{\odot}$, and surrounded by very thin inert hydrogen envelopes of mass of $m_{\rm env} \leq 0.02 \, \mathrm{m}_{\odot}$. they are thought to be formed when they lose most of the their hydrogen envelopes during the rgb phase of evolution, just before they ignite their he cores. the mechanism by which such rapid mass loss occurs is still not fully determined, but it is suspected that binary interactions via rlof play an important role in their formation, at least in the formation of hot subdwarf stars in the galactic field, where most sdb stars are found in binary systems. however, the fraction of binary sdb stars in globular clusters is very small, so other mechanisms, perhaps he enhancement via agb-star ejecta in clusters that have multiple populations, might play a role in their formation, this time from single-star progenitors. studies carried out using binary population synthesis from a theoretical point of view, following that of \cite{han2002a,han2003a} and \cite{han2007a}, can reveal much about the formation channels of such ehb stars, and the study described here builds on that, taking into account different chemical abundances (metallicities). asteroseismological studies of pulsating sdb stars have also contributed greatly to the determination of sdb star parameters, especially stellar masses, which has greatly helped astronomers to understand such stars. a comparison with theory is carried out using high-speed photometry. | hot subdwarf stars and binary evolution |
mass loss is a key physical process ruling the evolution of massive stars, whose impact propagates into galactic evolution, population synthesis models, the interpretation of high-redshift galaxies, explosive events like sn, and our understanding of the first stars. however, there are currently substantial uncertainties in the low-metallicity (z), low-luminosity regimes where the classical diagnostics, h-alpha and uv p-cygni profiles, fail to yield true mass-loss rates. only upper limits exist for most of the parameter space of interest and this is insufficient to inform the models of evolution. in contrast, the br-alpha line in the mid-ir breaks this degeneracy, enabling accurate determination of very low mass loss rates that are also independent from assumptions concerning wind inhomogeneities and wind x-ray emission. the technique has already been demonstrated for bright o-stars in the milky way. however, our primary low-z laboratory is the small magellanic cloud (smc), where br-alpha spectroscopy of o-stars is simply impossible for any facility other than jwst. we propose to exploit jwst's superb sensitivity in the thermal ir to determine the mass-loss rates of smc o-stars with thin winds for the first time. our results will serve to anchor the physics of radiation-driven wind theory that is so crucial for our understanding of massive star evolution and their impact on the universe. | what are the real mass loss rates of massive stars? |
post-starburst (or "e+a") galaxies are in transition between star-formation and quiescence, and represent a clear path for galaxies to transform their stellar populations, ism properties, and morphologies. many show signs of a recent galaxy-galaxy merger and a newly-evolved stellar bulge, and most have liner-like emission, which may indicate low luminosity agn activity. thus, the study of this short-lived phase of galaxy evolution can address the connections among mergers, star formation history, agn activity, and the evolution of the nucleus as a galaxy evolves onto the red sequence. the molecular gas content of these galaxies has been studied using single-dish co (1-0) and (2-1) observations from the iram-30m and alma observations of hcn (1-0). the recent star formation histories have been studied using uv/optical photometry and optical spectroscopy, fit using stellar population synthesis to determine the time since the recent starbursts ended. while post-starburst galaxies have stopped forming new stars, we have discovered that many have significant reservoirs of molecular gas remaining, which are depleted only after the starburst had already ended. young post-starburst galaxies have molecular gas reservoirs similar to normal star-forming galaxies, which decline to the levels of early type galaxies within 1-2 gyr. this rate of gas depletion is too rapid to be explained by the low star formation rates in these galaxies, so agn feedback may be responsible. recent alma observations show these galaxies also have low dense gas fractions, and the mechanisms which deplete the gas after the starburst may be the same as those which suppress the collapse of gas into denser states. | evolution of molecular gas reservoirs after galaxies stop forming stars |
we share the discovery of cool-j1241+2219, a lensed galaxy at z = 5.04 that is the brightest galaxy known at z > 5. this galaxy and the cluster lens were discovered as part of the cool-lamps project — chicago optically-selected strong lenses - located at the margins of public surveys — initiated to find strongly lensed systems in recent ground-based public imaging survey data, consisting primarily of a team of undergraduate students. cool-j1241+2219 is five times brighter than the prior record-holder at these redshifts, at zab = 20.5. we characterize the lensed galaxy, as well as the brightest cluster galaxy (bcg) of the lens cluster (at z=1.00), using ground-based grizjh band photometry and rest-frame uv and optical spectroscopy. we use stellar population synthesis (sps) modeling to characterize galaxy properties such as the stellar mass and star formation rate in the lensed galaxy. using cool-j1241+2219 as an anchor, we discuss the distribution of bright and lensed galaxies at z > 5. despite the loss of an entire observing season due to covid-19, the cool-lamps project has had continued success in 2020; we highlight some standout lensed sources discovered and studied so far. | cool-lamps: characterizing the brightest known galaxy in the redshift > 5 universe |
hex-p is a probe-class mission concept that will combine high spatial resolution x-ray imaging (<10 arcsec fwhm) and broad spectral coverage (0.1-150 kev) with an effective area far superior to current facilities (including xmm-newton and nustar) to enable revolutionary new insights into a variety of important astrophysical problems. a key science goal for hex-p is to understand the growth of supermassive black holes (smbhs) across cosmic time and its connection with galaxy evolution. we will present simulated hex-p observations of extragalactic fields, showcasing for the first time the detection of the seyfert-luminosity agn population in hard x-rays at cosmic noon (luminosities ~1043 erg/s in the 10-40 kev band). such observations will resolve >60% of the agn population contributing to the peak of the cosmic x-ray background, enabling more sensitive population synthesis of smbh growth in the context of the evolution of their host galaxies as probed by a range of multi-wavelength observations. we will also present the unprecedented capabilities of hex-p for studying the most heavily obscured agn. due to its uniquely sensitive broadband x-ray coverage, individual spectral studies will be capable of disentangling the geometry of the circum-nuclear environment from contaminating soft x-ray processes such as star formation at very low luminosities and accretion rates. complemented by multi-wavelength next-generation all-sky surveys, such studies will also investigate the connection between the obscurer and the surrounding host galaxy whilst in some of the highest column density regimes ever directly explored in x-rays. paired together with high spatial resolution hard x-ray imaging, hex-p will resolve and probe extreme sites of smbh growth in dust-obscured and/or merging galaxies hosting agn that are posited to be so buried in gas and dust that only hard x-rays can escape. the capabilities of hex-p are hence ideally suited for completing the black hole accretion and host galaxy co-evolution censuses in the nearby and more distant universe, and extremely complementary with next-generation multi-wavelength facilities such as the james webb space telescope, the vera c. rubin observatory and the laser interferometer space antenna. more information on hex-p, including the full team list, is available at hexp.org. | the high energy x-ray probe (hex-p): the cosmic history of black hole growth |
a galaxy's stellar mass-to-light ratio (m*/l) is a useful tool for converting luminosity to stellar mass (m*). however, the practical utility of m*/l inferred from stellar population synthesis (sps) models is limited by mismatches between the real and assumed models for star formation history (sfh) and dust geometry, both of which vary within galaxies. we present an analysis of the spatial variations in m*/l and their dependence on color, sfh, and dust across the disk of the nearby spiral galaxy m31. we derive a map of m* from color-magnitude diagrams of resolved stars in the panchromatic hubble andromeda treasury (phat) survey, then combine this m* map with the observed surface brightness to measure color vs. m*/l relations (cmlrs) in the optical and mid-infrared. we show that the cmlr residuals correlate with recent sfh, such that quiescent regions are offset to higher m*/l than star-forming regions at a fixed color. finally, we find a flatter optical cmlr than any sps-based cmlrs in the literature. we show that this is an effect of dust geometry, which is typically neglected but should be accounted for when using optical data to map m*, particularly for highly inclined galaxies. | mass-to-light ratios of spatially resolved stellar populations in m31 |
over the next five years, the bright galaxy survey (bgs) of the dark energy spectroscopic instrument (desi) will measure the spectra of 10 million galaxies out to z~0.5. the probabilistic value-added bgs (provabgs) will provide posteriors on the physical properties (e.g. m*, sfr, metallicity) for each of these galaxies and produce the most statistically powerful magnitude-limited sample for galaxy studies. in this talk, i will present the target selection and design of the desi bgs. i will also present the methods used to construct the provabgs, such as neural network emulators for stellar population synthesis, which enables tractable sampling of 10 million posteriors. lastly, i will discuss the potential of provabgs to advance galaxy science. | the probabilistic value-added catalog for the desi bright galaxy survey |
ngc 7793, ngc 300, m 33, and ngc 2403 are four nearby undisturbed and bulgeless low-mass spiral galaxies whose morphology and stellar mass are similar. they are ideal laboratories for studying disc formation scenarios and the histories of stellar mass growth. we constructed a simple chemical evolution model by assuming that discs grow gradually with continuous metal-free gas infall and metal-enriched gas outflow. by means of the classical χ2 method, applied to the model predictions, the best combination of free parameters capable of reproducing the corresponding present-day observations was determined, that is, the radial dependence of the infall timescale τ = 0.1r/rd + 3.4 gyr (rd is the disc scale length) and the gas outflow efficiency bout = 0.2. the model results agree excellently with the general predictions of the inside-out growth scenario for the evolution of spiral galaxies. about 80% of the stellar mass of ngc 7793 was assembled within the last 8 gyr, and 40% of the mass was assembled within the last 4 gyr. by comparing the best-fitting model results of the three other galaxies, we obtain similar results: 72% (ngc 300), 66% (ngc 2403), and 79% (m 33) of the stellar mass were assembled within the last ∼8 gyr (i.e. z = 1). these four disc galaxies simultaneously increased their sizes and stellar masses in time, and they grew in size at ∼0.30 times the rate at which they grew in mass. the scale lengths of these four discs now are 20%-25% larger than at z = 1. our best-fitting model predicted the stellar mass-metallicity relation and the metallicity gradients, constrained by the observed metallicities from hii-region emission line analysis, agree well with the observations measured from individual massive red and blue supergiant stars and population synthesis of sloan digital sky survey galaxies. | the growth history of local m 33-mass bulgeless spiral galaxies |
we present an updated analysis of the spatial variance of the dust attenuation law within galaxy ngc 3583. we utilize stellar population synthesis (sps) fitting on the resolved integral field unit (ifu) spectra provided by the manga survey in sdss dr17, in conjunction with aperture photometry from sdss and hst images. the addition of photometry provides significant improvement from our previous iteration, allowing us to constrain the metallicity and dust attenuation separately. we revisit our methods for fitting ifu spectra data for the dust law (including preparation of the localized spectra data with an adaptive blurring), and we discuss our results and their scientific implications, as we cross-check the fit with two independent pipelines, bagpipes and prospector. finally, we analyze how the inclusion of photometry in our fitting compares with the fitting of just spectra alone. | fitting sps models to ifu spectra and hst aperture photometry data: towards spatially resolved dust attenuation law within galaxy ngc3583 |
very massive stars (vms) are stars with masses in excess of 100 msun. they are formed in clusters massive enough to populate the initial mass function up to high masses. they are very luminous objects spectroscopically similar to, but much less evolved than, wolf-rayet stars. they dominate the integrated ultraviolet spectrum of young clusters. incorporating them in population synthesis is crucial to interpret spectroscopy of unresolved star forming regions and galaxies such as observed by the classy survey. however very few vms are directly observable in the local universe, especially in the uv: there are about ten such objects located either in 30 dor in the lmc or in the galactic cluster ngc 3603. we propose to nearly double the number of vms uv spectra by targeting the only other place in the local universe where vms can be studied individually in the uv: the two giant hii regions ngc595 and ngc604 in the triangulum galaxy m33. our goal is to obtain stis/g140l spectra of nine (candidate) vms previously identified in m33. we will determine the stellar and wind properties of vms at sub-lmc metallicity using atmosphere models. we will determine how their mass loss rate depend on luminosity and eddington parameter and implement these mass loss rates into new evolutionary models of vms. finally, we will develop population synthesis models using new empirical and synthetic spectra of vms. | very massive stars in m33 |
more than half of stars are in a binary system. when the two stars are close, the donor star could transfer mass onto the accretor star through the inner lagrangian point, where the roche-lobe of the two stars meets. other than mass, angular momentum is transferred which can spin-up the rotation of the accretor star. in a recent work of long-term spectroscopy binary survey, several fast rotating post mass-transfer stars in young open clusters have been found. in this work, we use the infrastructure functionality in population synthesis with detailed binary-evolution simulations (posydon, the next generation binary population synthesis code based on the mesa detailed binary evolutionary simulations), to establish a big low-mass binary grid focusing on the rotation of the accretor star. state-of-the-art magnetic braking presciptions are implemented to explain the data and the possible assistance in stellar gyrochronology in telling the age of those systems. in addition, we find that accretion through wind mass-transfer or even a small amount of mass through regular mass-transfer can account for the fast rotation measurements. ms acknowledges support through the gbmf8477 grant (pi kalogera). | fast rotating low-mass stars from post mass-transfer and post wind mass-transfer binary systems |
we present, for the first time, spatially resolved spectroscopy for the entire hickson compact group 31 obtained with the muse instrument at the vlt and an in-depth analysis of this compact group. to obtain a complete understanding of the system, we derived radial velocity and dispersion velocity maps, maps of the ionization mechanism of the system, chemical abundances and their distribution over the whole system, star formation rates and ages of the different star-forming regions, and the spatial distribution of the wolf-rayet stellar population. we also reconstructed the star formation history of the galaxies hcg 31 a, c, b, and f, measured the emission-line fluxes, and performed a stellar population synthesis. our main findings are: (i) that there is clearly disturbed kinematics due to the merger event that the system is experiencing; (ii) that the ionization is produced exclusively via star formation except for the nucleus of the galaxy hcg 31 a, where there is a small contribution of shocks; (iii) that there is low oxygen abundance distributed homogeneously through the system; (iv) that there is a prominent population of carbon wolf-rayet stars in the central zone of the group; and (v) that there are clear evidences of the tidal origin of the galaxies hcg 31 e, hcg 31 h, and hcg 31 f because they show quite high oxygen abundances for their stellar mass. all these findings are clear evidence that hcg 31 is currently in an early merging phase and manifesting a starburst in its central region. | a muse view of the multiple interacting system hcg 31 |
m31 is ideal for understanding the structure and stellar populations of spiral galaxies thanks to its proximity and our external vantage point. the andromeda optical & infrared disk survey (androids) has used megacam and wircam on the canada-france hawaii telescope to map the m31 bulge and disk out to r=40 kpc in ugrijks bands. through careful sky monitoring and modelling, androids is uniquely able to observe both the resolved stars and integrated spectral energy distributions (seds) over m31's entire disk (complimenting hst's phat program). by simultaneously fitting stellar populations with isochrones and sed models for m31, we can assess the systematic uncertainties of sed fits to more distant unresolved systems, and constrain the stellar populations that contribute to each bandpass. we pay close attention to the near-ir light of asymptotic giant branch (agb) stars in stellar population models. androids has also surveyed m31 in narrowband tio and cn bands, enabling a clean classification of carbon agb stars, and a mapping the ratio of carbon and m-type agb stars (c/m) across the entire disk. the correlation between c/m and stellar metallicity is useful for constraining the nir colors of more distant galaxies. we also present a hierarchical bayesian model of pixel-by-pixel stellar populations, yielding the most detailed map of m31's stellar mass and star formation history to date. we find that a full six-band optical-nir fit provides the best constraints to stellar mass, a triumph for modern nir stellar population synthesis models, though the results are consistent with an optical-only fits. fits based on the popular g-i color combination find m/l* ratios biased by 0.1 dex, while color-mass-to-light prescriptions in the literature may differ by 0.3 dex. this result affirms that panchromatic sed modelling is crucial even for stellar mass estimation, let alone age and metallicity. overall, we estimate the stellar mass of m31, within r=30 kpc, to be 10.3 (+2.3, -1.7) x 1010 m⊙. | andromeda optical & infrared disk survey: stellar populations and mass decomposition |
using archival near-ir photometry, we identify 51 of the k-band brightest red supergiants (rsgs) in ngc 6822 and compare their physical properties with stellar evolutionary model predictions. we first use gaia parallax and proper motion values to filter out foreground galactic red dwarfs before constructing a j-k versus k color-magnitude diagram to eliminate lower-mass asymptotic giant branch star contaminants in ngc 6822. we then cross match our results to previously spectroscopically confirmed rsgs and other ngc 6822 content studies and discuss our overall completeness, concluding that radial velocity alone is an insufficient method of determining membership in ngc 6822. after transforming the j and k magnitudes to effective temperatures and luminosities, we compare these physical properties with predictions from both the geneva single-star and binary population and spectral synthesis (bpass) single and binary-star evolution tracks. we find that our derived temperatures and luminosities match the evolutionary model predictions well, however, the bpass model, which includes the effects of binary evolution, provides the best overall fit. this revealed the presence of a group of cool rsgs in ngc 6822, suggesting a history of binary interaction. we hope this work will lead to further comparative rsg studies in other local group galaxies, opportunities for direct spectroscopic follow-up, and a better understanding of evolutionary model predictions. | locating red supergiants in the galaxy ngc 6822 |
i describe and demonstrate a new approach to using spectroscopic data to exploit poisson sampling fluctuations in unresolved stellar populations. the method is introduced using spectra predicted for independent samples of stars from a 10 gyr population using a simple stochastic spectral synthesis model. a principal components analysis shows that >99 per cent of the spectral variation in the red-optical can be attributed to just three 'fluctuation eigenspectra', which can be related to the number of giant stars present in each sample, and their distribution along the isochrone. the first eigenspectrum effectively encodes the spectrum of the coolest giant branch stars, and is equivalent to the ratio between high- and low-flux pixels discussed in previous literature. the second and third eigenspectra carry higher-order information from which the giant-star spectral sequence can in principle be reconstructed. i demonstrate the method in practice using observations of part of ngc 5128, obtained with the muse narrow-field adaptive optics mode. the expected first eigenspectrum is easily recovered from the data, and closely matches the model results except for small differences around the ca ii triplet. the second eigenspectrum is below the noise level of the present observations. a future application of the method would be to the cores of giant ellipticals to probe the spectra of cool giant stars at high metallicity and with element abundance patterns not accessible in the milky way. | probing cool giants in unresolved galaxies using fluctuation eigenspectra: a demonstration using high-resolution muse observations of ngc 5128 |
galaxy formation and evolution involves a variety of effectively stochastic processes operating over a range of timescales. we model variability in galaxy star formation histories (sfhs) using physically motivated log-gaussian processes that incorporate variability due to stochastic gas inflows, baryon cycling and gmc creation and destruction. using stellar population synthesis models, we explore how changes in model stochasticity can affect spectral signatures across galaxy populations with properties similar to the milky way and present-day dwarfs as well as at higher redshifts. we find that perturbing the stochasticity model by changing the amount of stochasticity or the effective timescales associated with the physical processes leaves unique spectral signatures across idealised and more realistic galaxy populations. through distributions of spectral features, these provide testable predictions with larger sample sizes of galaxy populations from present and upcoming surveys with jwst & ngrst. | detectable signatures of star formation stochasticity in galaxy spectra |
eclipsing binary stars are significant objects for understanding stellar evolution, stellar population synthesis, and galaxy dynamics. thanks to the increasing number of high-quality photometric data of space observations, the sensitivity of the fundamental astrophysical parameters (mass m, radius r) has risen and this situation has highlighted the importance of eclipsing binary stars once again. there are known relations between m and luminosity (l) for the eclipsing binary systems, especially for the detached binaries. however, in these m - l relations, some break-points appear and those points need to be re-examined with accurate m and l parameters of stars located at these areas. one of these break-points presents around the solar mass. therefore, this study focuses on a tess field object tic 284613090 which is an eccentric binary system containing two solar-type components. in the study, the fundamental parameters of the binary component stars were precisely obtained by a simultaneous analysis of the radial velocities and the tess light curve. as a result, the masses and radii of the primary and secondary binary components were found to be m1 = 1.030 (8) m⊙, m2 = 1.019 (8) m⊙ and r1 = 1.611 (5)r⊙, r2 = 1.485 (5) r⊙, respectively. when the evolutionary status of the component stars was examined, it turned out that they are approaching the end of their main sequence evolution and the age of the system is 9.65 (20) gyr. as a result of binary evolutionary models, it was also found that tic 284613090 started its evolution with an orbital period of 11.83 days and an eccentric orbit with a value of e = 0.227. the position of the binary components in the m - l relation was examined as well and showed consistency with the relation. | detailed analysis of an eccentric tess binary star with solar-type components: tic 284613090 |
multimessenger observations of the neutron star merger gw170817 and its kilonova proved that neutron star mergers can synthesize large quantities of r-process elements. if neutron star mergers in fact dominate all r-process element production, then the distribution of kilonova ejecta compositions should match the distribution of r-process abundance patterns observed in stars. the lanthanide fraction (xla) is a measurable quantity in both kilonovae and metal-poor stars, but it has not previously been explicitly calculated for stars. here we compute the lanthanide fraction distribution of metal-poor stars ([fe/h]{<}-2.5) to enable comparison to current and future kilonovae. the full distribution peaks at log xla~-1.8, but r-process-enhanced stars ([eu/fe]>0.7) have distinctly higher lanthanide fractions: logxla>~-1.5. we review observations of gw170817 and find general consensus that the total logxla=-2.2+/-0.5, somewhat lower than the typical metal-poor star and inconsistent with the most highly r-enhanced stars. for neutron star mergers to remain viable as the dominant r-process site, future kilonova observations should be preferentially lanthanide-rich (including a population of ~10% with logxla>-1.5). these high-xla kilonovae may be fainter and more rapidly evolving than gw170817, posing a challenge for discovery and follow-up observations. both optical and (mid-)infrared observations will be required to robustly constrain kilonova lanthanide fractions. if such high-xla kilonovae are not found in the next few years, that likely implies that the stars with the highest r-process enhancements have a different origin for their r-process elements. (2 data files). | vizier online data catalog: lanthanide fraction distribution of metal-poor stars (ji+, 2019) |
we investigate the mass-metallicity relation (mzr)for galaxies in the abell cluster ac114 from 7 h of vimos/mr data collected at the european southern observatory-very large telescope in 2009. the dynamical analysis completed in our previous paper allowed us to select cluster members, whose spectra are here analysed with stellar population synthesis models. active and passive galaxies are identified based on the presence/absence of the [o ii] λ3727, [o iii] λλ4959, 5007 and/or hβ emission lines, depending on the galaxy redshift. we find that active galaxies have lower average masses than passive ones, and have lower average metallicities. the mzr of the cluster is found to be steeper than that for galaxies in the local universe. | the galaxy cluster ac114 - ii. stellar populations and the mass-metallicity relation |
megara (multi espectrógrafo en gran telescopio canarias de alta resolución para astronomía) is the optical integral-field and multi-object spectrograph at the gran telescopio canarias. we have created megastar , an empirical library of stellar spectra obtained using megara at high resolution, $r=20\, 000$ (full width at half-maximum), available in two wavelength ranges: one centred on hα, from 6420 to 6790 å; and the other centred on the ca ii triplet, from 8370 to 8885 å (hr-r and hr-i volume phase holographic (vph)-grating configurations). in this work, we use megastar spectra, a combination of these two short wavelength intervals, to estimate the stellar parameters, namely the effective temperature, surface gravity, and metallicity (and their associated errors), for a sample of 351 megastar members with spectral types earlier than b2. we applied a χ2-technique by comparing megastar data with theoretical stellar models. for those stars with stellar parameters derived in the literature, we obtained a good agreement between the published parameters and ours. in addition to the stellar parameters, we also provide several products, such as the rectified spectra, radial velocities, and stellar indices, for this sample of stars. in the near future, we will use megastar spectra and their derived stellar parameters to compute stellar population evolutionary synthesis models, which will contribute to a better interpretation of star cluster and galactic spectra obtained with megara. | megastar - iii. stellar parameters and data products for dr1 late-type stars |
the final orbital configuration of a planetary system is shaped by both its early star-disc environment and late-stage gravitational interactions. assessing the relative importance of each of these factors is not straightforward due to the observed diversity of planetary systems compounded by observational biases. our goal is to understand how a planetary system may change when planetesimal accretion and planet migrations stop and secular gravitational effects take over. our approach starts with a novel classification of planetary systems based on their orbital architecture, validated using approximate bayesian computation methods. we apply this scheme to observed planetary systems and also to ~400 synthetic systems hosting ~5000 planets, synthesized from a monte carlo planet population model. our classification scheme robustly yields four system classes according to their planet masses and semimajor axes, for both observed and synthetic systems. we then estimate the orbital distribution density of each of the synthetic systems before and after dynamically evolving for 0.1-1 myr using a gravitational + collisional n-body code. using the kullback-leibler divergence to statistically measure orbital configuration changes, we find that ≲10 per cent of synthetic planetary systems experience such changes. we also find that this fraction belongs to a class of systems for which their centre of mass is very close to their host star. although changes in the orbital configuration of planetary systems may not be very common, they are more likely to happen in systems with close-in, massive planets, with f- and g-type host-stars and stellar metallicities [fe/h] >0.2. | a bayesian monte carlo assessment of orbital stability in the late stages of planetary system formation |
for the upcoming planetary transits and oscillation of stars (plato) satellite mission, a large number of target stars are required to yield a statistically significant number of planet transits. locating the centres of the long duration observational phase (lop) fields closer to the galactic plane will increase the target star numbers but also the astrophysical false positives (fps) from blended eclipsing binary systems. we utilize the binary stellar evolution and population synthesis code, to create a complete synthetic stellar and planetary population for the proposed southern lop field (lops0), as well as for a representative portion of the northern lop field (lopn-sub). for lops0, we find an overall low fp rate for planets smaller than neptunes. the fp rate generally shows little variation with galactic longitude (l), and a modest increase with decreasing galactic latitude (|b|). the location of the lops field centre within the current allowed region is not strongly constrained by fps. analysis of lopn-sub suggests a markedly increased number of fps across the full range of planet radii at low |b| resulting in approximately twice the percentage of fp detection rate in the lopn-sub compared to the corresponding southern field segment in the planet radius range -0.2 < log (r/r⊕) ≤ 0.4. however, only a few per cent of fully eclipsing fps in lops0 in this radius range have periods between 180 and 1000 d so the vast majority of fps are expected to be outside the period range of interest for plato. | population study of astrophysical false positive detections in the southern plato field |
aluminium-26 is a radioactive isotope which can be synthesized within asymptotic giant branch (agb) stars, primarily through hot bottom burning. studies exploring 26al production within agb stars typically focus on single-stars; however, observations show that low- and intermediate-mass stars commonly exist in binaries. we use the binary population synthesis code binary_c to explore the impact of binary evolution on 26al yields at solar metallicity both within individual agb stars and a low/intermediate-mass stellar population. we find the key stellar structural condition achieving most 26al overproduction is for stars to enter the thermally pulsing agb (tp-agb) phase with small cores relative to their total masses, allowing those stars to spend abnormally long times on the tp-agb compared to single-stars of identical mass. our population with a binary fraction of 0.75 has an 26al weighted population yield increase of 25 per cent compared to our population of only single-stars. stellar-models calculated from the mt stromlo/monash stellar structure program, which we use to test our results from binary_c and closely examine the interior structure of the overproducing stars, support our binary_c results only when the stellar envelope gains mass after core-he depletion. stars which gain mass before core-he depletion still overproduce 26al, but to a lesser extent. this introduces some physical uncertainty into our conclusions as 55 per cent of our 26al overproducing stars gain envelope mass through stellar wind accretion onto pre-agb objects. our work highlights the need to consider binary influence on the production of 26al. | aluminium-26 production in low- and intermediate-mass binary systems |
massive binaries play a vital role in governing the evolution of dense stellar systems such as star clusters. the interplay between massive star evolution and cluster dynamics can provide valuable insight into the formation of exotic binaries observed by electromagnetic and gravitational-wave observatories. however, the current tools for computing the evolution of clusters often rely on outdated models for the lives of massive stars. in this talk, i will discuss the uncertain and model-dependent evolution of massive stars and share results from metisse, a new method for estimating stellar evolution. by using metisse within binary population synthesis code cosmic, i will demonstrate how variations in stellar evolution parameters can impact which areas of the binary parameter space result in compact binary mergers. ultimately, this knowledge will help us better understand the intricate processes involved in the evolution of both star clusters and the formation of unique binary systems. | looking at single and binary populations through the lens of massive stellar evolution |
combining the cloudy photoionization code with updated stellar population synthesis results, we simultaneously model the mir $\rm{[ne {}{\small iii}]}/\rm{[ne {}{\small ii}]}$ versus $\rm{[o {}{\small iv}]}/\rm{[ne {}{\small iii}]}$, the mir-fir $\rm{[ne {}{\small iii}]}/\rm{[ne {}{\small ii}]}$ versus $\rm{[o {}{\small iv}]}/\rm{[o {}{\small iii}]}$ and the classical bpt diagnostic diagrams. we focus on the properties of optically classified h ii galaxies that lie in the normal star forming zone in the mir diagnostic diagram. we find that a small fraction of our models lie in this zone, but most of them correspond to the lowest explored metallicity, z* = 0.0002, at age ~1 gyr. this value of z* is, by far, lower than the values derived for these galaxies from optical emission lines, suggesting that the far-uv emission produced by post-agb stars (a.k.a. holmes, hot low-mass evolved stars) is not the source of ionization. instead, shock models can easily reproduce this part of the mir diagram. we suggest that it is likely that some of these galaxies have been misclassified and that in them, shocks, produced by a weak agn-outflow, could be an important source of ionization. using a subset of our models, we derive a new demarcation line for the maximal contribution of retired galaxies in the bpt diagram. this demarcation line allows for a larger contamination from the neighbouring agn-dominated region. considering the importance of disentangling the different ionizing mechanisms in weak or deeply obscured systems, new observational efforts to classify galaxies both in the optical and ir are required to better constrain this kind of models and understand their evolutionary paths. | on the origin of optical and ir emission lines in star-forming galaxies |
this document describes bincodex, a common format for the output of binary population synthesis (bps) codes agreed upon by the members of the lisa synthetic ucb catalogue group. the goal of the format is to provide a common reference framework to describe the evolution of a single, isolated binary system or a population of isolated binaries. | bincodex: a common output format for binary population synthesis |
in the local universe, it is observed that the x-ray luminosity (lx) of high-mass x-ray binary (hmxb) populations is correlated with the host galaxy's star formation rate (sfr). recent x-ray studies of high-redshift galaxies find a positive evolution of this correlation with redshift. this trend is attributed to the formation of more luminous hmxbs in lower metallicity (z) environments, as predicted by binary population synthesis models. while there is observational evidence that hmxb populations in nearby low-z dwarf galaxies have enhanced lx/sfr, the correlation between lx, sfr, and z is poorly constrained and, due to the difficulty of obtaining z measurements at high redshift, it has yet to be proven that the redshift evolution of lx/sfr is driven by the z-dependence of hmxbs. better understanding how hmxb lx varies with z and redshift will constrain: (1) whether hmxbs in low-z environments can be progenitors of the heavy bh binaries discovered by gravitational wave observatories, (2) the contribution of hmxbs to the x-ray heating and reionization of gas in the early universe, and (3) estimates of hmxb contamination to x-ray searches for low-luminosity agn and intermediate mass black holes. we present preliminary results of a set of x-ray stacking studies of star-forming galaxies at different redshifts, whose goal is to test the connection between the redshift evolution and z-dependence of hmxbs. we use samples of galaxies at z~0.3, z~0.7, and z~2 with z measurements from the hcosmos, zcosmos, and mosdef surveys, respectively. stacking chandra data from the deep extragalactic fields in which these galaxies reside, we measure the lx-sfr-z relation at different redshifts and compare our results to the lx-sfr-z relation measured in the local universe and to predictions from population synthesis models. these studies provide the first direct tests that the redshift evolution of the lx/sfr of hmxbs is driven by metallicity. | connecting the metallicity dependence and redshift evolution of x-ray binaries |
it is proposed that a one-off fast radio burst (frb) with periodic structure may be produced during the inspiral phase of a binary neutron star (bns) merger. in this paper, we study the event rate of such kind of frb. we first investigate the properties of two one-off frbs with periodic structure (i.e., frb 20191221a and frb 20210213a) in this scenario, by assuming a fast magnetosonic wave is responsible for their radio emission. for the luminosities and periods of these bursts, it is found that for the nss in the premerger bns, magnetic field strengths of b ≳ 1012 g are required. this is relatively high compared with those of most of the bnss observed in our galaxy, of which their magnetic fields are around 109 g. since the observed bnss in our galaxy are binaries that have not suffered a merger, a credible event rate of bns-merger-originated frbs should be estimated by considering the evolution of both the bns systems and their magnetic fields. based on population synthesis and adopting decaying magnetic fields of the nss, we estimate the event rate of bns mergers relative to their final magnetic fields. we find that rapidly merging bnss tend to merge with high magnetization, and the event rate of bns-merger-originated frbs, i.e., bns mergers with both nss' magnetic fields being higher than 1012 g, is ~8 × 104 yr-1 (19% of all bns mergers) for redshifts z < 1. | event rate of fast radio bursts from binary neutron star mergers |
as one of the three major experiments of the fourth-generation sloan digital sky survey (sdss-iv), the mapping nearby galaxies at apatch point observatory (manga) survey has obtained high-quality integral field spectroscopy (ifs) with a resolution of 1-2 kpc for ~ 104 galaxies in the local universe during its six-year operation from july 2014 through august 2020. it is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study. in the past years we have made lots of efforts to develop a novel technique of full spectral fitting, which estimates a model-independent dust attenuation curve from each spectrum, thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models. we have applied our technique to the final data release of manga, and obtained measurements of stellar population properties and emission line parameters, as well as the kinematics and dust attenuation of both stellar and ionized gas components. in this paper we describe our technique and the content and format of our data products. the whole dataset is publicly available in science data bank with the link https://doi.org/10.57760/sciencedb.j00113.00088. | measuring stellar populations, dust attenuation and ionized gas at kpc scales in 10010 nearby galaxies using the integral field spectroscopy from manga |
millisecond pulsars (msps) are believed to be old neutron stars that have undergone spin-up by the accreting material from the donor. however, the discovery of eccentric msps (emsps) in the galactic field challenges such a scenario of producing msp-white dwarf systems only in a circular orbit. as the orbital periods and companion masses of these emsps are located in a narrow range, it is reasonable to postulate that they have the same origin. although many models have been proposed to interpret the origin of emsps, the origin of the narrow range of the orbital period is still an open question. the accretion-induced collapse (aic) of the oxygen-neon white dwarf is considered to be an important pathway to form msps, as it is expected to result in the formation of msps in a circular orbit due to tidal circularization. here we revisited this scenario using binary population synthesis including the specific circularization calculation. our results indicate that binaries with insufficient circularization in this scenario can evolve into emsps. the narrow initial binary parameters required by insufficient circularization can naturally account for the narrow range of the orbital period. although the evolution of the white dwarf aic process is not yet well understood, the characteristic of a narrow range in the orbital period of emsps can still set constraints on the physics of their evolution. | on the formation of eccentric millisecond pulsars by accretion-induced collapse of massive white dwarfs |
we present a preliminary exploration of the impact of the initial conditions in our global model of planet formation on the observable properties of protoplanetary disks. we implemented different numerical modules to calculate the initial parameters of the model, such as masses and sizes of the disks, from statistical distributions inferred observationally. in particular, using a population synthesis that computes the evolution of protoplanetary disks by viscous accretion and x-ray photoevaporation, we explore which initial parameters and distributions are capable of reproducing the fraction of stars with protoplanetary disks observed in stellar populations of different ages. | síntesis poblacional de discos protoplanetarios |
theoretical studies of binary star populations often rely on binary population synthesis, a technique that generates mock populations based on our best understanding of how binary stars evolve. current codes typically use some version of the two-decade-old legacy code sse/bse. while revolutionary in its day, sse/bse suffers from several known deficiencies, and an improved method is found wanting. in this talk i will discuss posydon, a next-generation binary population synthesis code built upon the binary module within the mesa stellar evolution code. i will discuss how posydon synthesizes binary populations, in turn resolving issues introduced by sse/bse, and i will present preliminary results on gravitational wave populations. | posydon: a binary population synthesis code based on mesa |
white dwarfs are fossil stars that can encode valuable information about the formation, evolution and other properties of the different galactic stellar populations. they are the direct descendants of main-sequence stars with masses ranging from ∼0.8 m⊙ to ∼10 m⊙, which means that over 95% of the stars in our galaxy will eventually become white dwarfs. this fact, correlated with the excellent quality of modern white dwarf cooling models, clearly marks their potential as cosmic clocks for estimating the ages of galactic stellar populations, as well as place white dwarfs as privileged objects in understanding several actual astrophysical problems. stellar population synthesis methods (tinsley, 1968) use theoretical evolutionary sequences to reproduce luminosities, temperatures and other parameters building up to a synthetic population that can be readily compared to an observed sample of stars. such techniques are perfect for the study of the different white dwarf populations in our galaxy and their strength has only grown in recent years, fueled both by improved evolutionary sequences and detailed cooling tracks and also by the ever growing samples of white dwarfs identified through modern survey missions. in particular, the work presented in this thesis uses an updated population synthesis code based on previous versions of the code from our group (garcía-berro et al., 1999; torres et al., 2002; garcía-berro et al., 2004; torres et al., 2005; camacho et al., 2014). our synthetic population code, based on monte carlo statistical techniques, has been extensively used in the study of the disk (garcía-berro et al., 1! 999; torres et al., 2001; torres & garcía-berro, 2016) and halo (torres et al., 2002; garcía-berro et al., 2004) single white-dwarf population, white dwarf plus main sequence stars (camacho et al., 2014), as well as open clusters such as ngc 6791 (garcía-berro et al., 2010; garcía-berro et al., 2011) or globular clusters, as 47 tuc (garcía-berro et al., 2014). in this thesis we investigate different properties of single and binary white dwarf populations in the galactic disk and halo. we first study the effect of progenitor metallicity on the thin disk white dwarf luminosity function. stellar metallicity is an important parameter in computing both main-sequence evolutionary sequences and white dwarf cooling tracks. at the same, studies of the metallicity distribution function for the galactic disk have shown that both high and low-metallicity stars can be found throughout the entire mass range, although a clear dependence between age and metallicity has yet to be proven and more recent findings actually show little correlation. with this in mind, we test two different age-metallicity relations, one assuming a gaussian distribution of metallicity around the solar value, the other one a decreasing relation between age and metallicity. we take into account the influence of metallicity on both main sequence lifetimes and white dwarf s! tellar parameters. finally, we compute the theoretical white dwarf luminosity function applying the observational selection criteria of two different surveys, the sloan digital sky survey (sdss) and the supercosmos sky survey (sss). next, we compute the white dwarf luminosity, mass and cumulative age functions derived from a sample of da white dwarfs obtained from the lamost spectroscopic survey of the galactic anti-center (lss-gac). we also derive the local space density and the formation rate for da white dwarf. given that both the observed mass distribution obtained from this sample and that derived from the local sample of white dwarfs present an apparent excess of massive white dwarfs, we investigate the possibility of accounting for this excess by reproducing the white dwarf population of the thin disk under different sets of initial assumptions, accounting also for selection criteria and observational biases. another issue that we investigate is the robustness of the halo white dwarf luminosity function employing different models for the initial mass function, density profile and stellar formation history. we also analyze if the white dwarf luminosity function can be used as a means to discriminate the role played by residual hydrogen burning in the atmospheres of low-mass white dwarfs. this process is known to become a significant source of energy for white dwarfs descending from very low metallicity progenitors, such as those that characterize the galactic halo population. lastly, we simulate the white dwarf-main sequence (wd+ms) binary population of the galactic disk and compare it to the parameter distributions from the largest and most recent wd+ms catalog derived from the sdss (rebassa-mansergas et al., 2016b). we not only reproduce the selection criteria, but we also account for spectroscopic completeness, observational errors and other biases that affect the sample. we use the observed population as a benchmark for constraining several important physical quantities specific to binary evolution, such as the initial mass ratio distribution and also the common envelope parametrization. this thesis is based on three published papers, cojocaru et al. (2014), rebassa-mansergas et al. (2015) and cojocaru et al. (2015) and another work in preparation. | population synthesis studies of the white dwarfs of the galactic disk and halo |
stellar evolution models predict that rotation induces the mixing of chemical species, with the subsequent surface abundance anomalies relative to single non-rotating models, even during the main sequence (ms) evolution. the lack of measurable nitrogen surface enrichment in ms rotating stars, such as be stars, has been interpreted as being in conflict with evolutionary models (e.g. lennon et al. 2005; hunter et al. 2008). in order to have an insight on the kind of ambient we do or we do not expect to find enriched rotating stars, we use our new population synthesis code, to produce synthetic intermediate-mass stellar populations fully accounting for stellar rotation effects, and study their evolution in time. | evolution of the rotational properties and nitrogen surface abundances of b-type stellar populations |
the dynamical stability of quadruple-star systems has traditionally been treated as a problem involving two 'nested' triples which constitute a quadruple. in this novel study, we employed a machine learning algorithm, the multilayer perceptron (mlp), to directly classify 2 + 2 and 3 + 1 quadruples based on their stability (or long-term boundedness). the training data sets for the classification, comprised of 5 × 105 quadruples each, were integrated using the highly accurate direct n-body code mstar. we also carried out a limited parameter space study of zero-inclination systems to directly compare quadruples to triples. we found that both our quadruple mlp models perform better than a 'nested' triple mlp approach, which is especially significant for 3 + 1 quadruples. the classification accuracies for the 2 + 2 mlp and 3 + 1 mlp models are 94 and 93 per cent, respectively, while the scores for the 'nested' triple approach are 88 and 66 per cent, respectively. this is a crucial implication for quadruple population synthesis studies. our mlp models, which are very simple and almost instantaneous to implement, are available on github, along with python3 scripts to access them. | quadruple-star systems are not always nested triples: a machine learning approach to dynamical stability |
the ionizing radiation of young and massive stars is a crucial form of stellar feedback. most ionizing (lyman-continuum; lyc, λ < 912å) photons are absorbed close to the stars that produce them, forming compact h ii regions, but some escape into the wider galaxy. quantifying the fraction of lyc photons that escape is an open problem. in this work, we present a seminovel method to estimate the escape fraction by combining broadband photometry of star clusters from the legacy extragalactic uv survey (legus) with h ii regions observed by the star formation, ionized gas, and nebular abundances legacy survey (signals) in the nearby spiral galaxy ngc 628. we first assess the completeness of the combined catalogue, and find that 49 per cent of h ii regions lack corresponding star clusters as a result of a difference in the sensitivities of the legus and signals surveys. for h ii regions that do have matching clusters, we infer the escape fraction from the difference between the ionizing power required to produce the observed h ii luminosity and the predicted ionizing photon output of their host star clusters; the latter is computed using a combination of legus photometric observations and a stochastic stellar population synthesis code slug (stochastically lighting up galaxies). overall, we find an escape fraction of ${f}_{\textrm {esc}}= 0.09^{+0.06}_{-0.06}$ across our sample of 42 h ii regions; in particular, we find h ii regions with high fesc are predominantly regions with low $\operatorname{h\alpha }$-luminosity. we also report possible correlation between fesc and the emission lines $\rm [o\, \rm {\small ii}]/[n\, \rm {\small ii}]$ and $\rm [o\, \rm {\small ii}]/h\beta$. | constraining the lyc escape fraction from legus star clusters with signals h ii region observations: a pilot study of ngc 628 |
the possible co-evolution between galaxies and their central supermassive black holes is supported by the similarity in shape between the star formation rate density (sfrd) and black hole accretion rate density (bhard) out to z$\sim$ 3. this apparent connection between bh growth and star formation is only established globally; while both trends peak at z$\sim$ 2, the amount of stellar and black hole mass assembly occurring within the same galaxies is unknown. computing these trends for the same galaxies will mitigate the present sample mismatch and can be accomplished with an ir-selected sample; however, the approach relies on a robust understanding of broadband uv-fir sed fitting to reliably decompose agn and sf luminosities over a range of agn strengths. uv-fir sed fitting is an effective way to disentangle emission between star formation (sf) and active galactic nuclei (agn) in galaxies with sufficient broadband photometry. the precision of this approach, however, is affected by the sparse mid-ir data presently available in statistically large samples and the variety of agn sed shapes predicted by radiative transfer torus models. given these constraints, the use of sed fitting to characterize supermassive black hole accretion is more uncertain in composite agn/sf galaxies, when the mid-ir sed is \textit{not} overwhelmed by agn emission. this is significant, as composite galaxies are ubiquitous in nature ($\sim$ 50-70\% of ir-selected samples) and may represent either weak, low-luminosity agn or a more luminous agn population that is heavily dust obscured. in this thesis we construct the sfrd and bhard for the same sample of galaxies, selected at 250$\mu$m in the cosmos field, testing a variety of agn sed decomposition methods and agn templates. we find that employing optically thick agn torus models results in a bhard that is higher than current x-ray observations predict but is more similar to the compton-thick bhard predicted by x-ray population synthesis models. this large population of luminous obscured agn, revealed by sed decomposition, results in a bhard trend that drops more rapidly with decreasing redshift than the corresponding sfrd. our results imply that universal mass assembly via smbh growth and sf are not directly linked to grow their mass at similar rates across similar epochs. | the coeval mass assembly of the universe via supermassive black hole accretion and star formation in galaxies |
the study of orbital resonances allows for the constraint of planetary properties of compact systems. mean motion resonance occurs when two or more planets repeatedly exchange angular momentum and energy as they orbit their host star, since the planets will always conjunct at the same point in their orbits. we can predict a system's resonances by observing the orbital periods of the planets, as planets in or near mean motion resonance have period ratios that reduce to a ratio of small numbers. however, a period ratio near commensurability does not guarantee a resonance; we must study the system's dynamics and resonance angles to confirm resonance. because resonances require in-depth study to confirm, and because two-body resonances require a measurement of the eccentricity vector which is quite challenging, very few resonant pairs or chains have been confirmed. we thus remain in the era of small number statistics, not yet able to perform large population synthesis or informatics studies. to address this problem, we build a python package to find, confirm, and analyze mean motion resonances, primarily through n-body simulations. we verify our package by recovering the known resonances of kepler-80 and kepler-223. we then demonstrate the package's functionality and potential by confirming new resonances, characterizing the mass-eccentricity degeneracy of kepler-80g, and exploring the likelihood of an exterior giant planet in kepler-80 and kepler-223. we also study the formation history of k2-138 and constrain the planets' masses and orbital parameters. | new python package to find, confirm, and characterize mean motion resonances |
local star-forming dwarf galaxies provide the only laboratory in which extremely metal-poor stellar populations like those encountered at the highest redshifts can be studied in detail. over hundreds of orbits, hubble has completely revolutionized our view of young star-forming systems, extending our ultraviolet vision to substantially younger ages and lower metallicities than previously seen. this exploration has revealed a rare population of extremely metal-poor systems dominated by massive stars that power uv nebular emission lines at strengths approaching that encountered in the first jwst spectra at z>~9. unfortunately, the existing local uv spectra leave the faint continuum signatures of these massive stars effectively unconstrained in the lowest-metallicity and most extreme nebular emitters. here we propose to remedy this by completing extraordinarily-deep 40-50 orbit spectra for the two brightest star forming regions known that are likely to harbor massive stars at or below 5% solar. these spectra will directly constrain the stellar photospheric and wind signatures imprinted on the fuv continuum which hold the key to understanding the hot stars that dominate high-ionization nebular line emission. comparing these galaxies to stellar population synthesis prescriptions will provide our best hope of empirically calibrating the models that will continue to be used routinely at high-redshift in the coming years. without these crucial uv observations, our understanding of the highest-redshift and lowest-mass systems that jwst and the elts will uncover will suffer from substantial systematic model uncertainties unaddressable without a uv space telescope. | mega-deep uv spectroscopy of star-forming galaxies: completing the picture of the extremely metal-poor massive stars underlying high-ionization uv nebular emission |
the spectra of distant galaxies contain unique information about the star formation rate and history of the universe at high redshift. jwst affords new opportunities to observe galaxies at high redshift as never before. yet, our ability to uncover details about the history of the universe are only as good as the spectral models they are compared against. the previous generation of stellar population models treat stellar binaries in only an approximate way, if at all. however, stellar mergers generate anomalously massive stars well after a starburst event, mass transfer strips the envelope off stars producing copious uv ionizing photons, and accreting compact objects producing luminous x-ray binaries. here we propose to use the next-generation binary population synthesis code, posydon, to create a new generation of synthetic spectral models. posydon self-consistently evolves the structure of both stars, including stellar rotation, simultaneously with the orbital evolution. we propose to couple these models with detailed stellar atmospheric spectral models for both h-rich and he-rich stars, allowing us to produce a new generation of spectral models for any arbitrary star formation history and metallicity. finally, we propose to produce a library of spectral models for integration into widely used galaxy modeling codes such as bagpipes, cigale, and prospector. | a new-generation of synthetic stellar population spectral models containing stellar binaries |
we present a measurement of νe interactions from the fermilab booster neutrino beam using the microboone liquid argon time projection chamber to address the nature of the excess of low energy interactions observed by the miniboone collaboration. three independent νe searches are performed across multiple single electron final states, including an exclusive search for two-body scattering events with a single proton, a semi-inclusive search for pionless events, and a fully inclusive search for events containing all hadronic final states. with differing signal topologies, statistics, backgrounds, reconstruction algorithms, and analysis approaches, the results are found to be either consistent with or modestly lower than the nominal νe rate expectations from the booster neutrino beam and no excess of νe events is observed. | search for an excess of electron neutrino interactions in microboone using multiple final-state topologies |
we propose a novel dispersive treatment of the so-called inner radiative correction to the neutron and nuclear β decay. we show that it requires knowledge of the parity-violating structure function f3(0 ) that arises from the interference of the axial vector charged current and the isoscalar part of the electromagnetic current. by isospin symmetry, we relate this structure function to the charged current inelastic scattering of neutrinos and antineutrinos. applying this new data-driven analysis we obtain a new, more precise evaluation for the universal radiative correction δrv ,new=0.02467 (22 ) that supersedes the previous estimate by marciano and sirlin, δrv=0.02361 (38 ). the substantial shift in the central value of δrv reflects in a respective shift of vu d and a considerable tension in the unitarity constraint on the first row of the cabibbo-kobayashi-maskawa matrix which is used as one of the most stringent constraints on new physics contributions in the charged current sector. we also point out that dispersion relations offer a unifying tool for treating hadronic and nuclear corrections within the same framework. we explore the potential of the dispersion relations for addressing the nuclear structure corrections absorbed in the f t values, a crucial ingredient alongside δrv in extracting vu d from superallowed nuclear decays. in particular, we estimate the quenching of the free neutron born contribution in the nuclear environment, corresponding to a quasielastic single-nucleon knockout, and find a significantly stronger quenching effect as compared to currently used estimates based on the quenching of spin operators in nuclear transitions. this observation suggests that the currently used theoretical uncertainties of f t values might be underestimated and require a renewed scrutiny, while emphasizing the importance of new, more precise measurements of the free neutron decay where nuclear corrections are absent. | dispersive evaluation of the inner radiative correction in neutron and nuclear β decay |
genie is a suite of products for the experimental neutrino physics community. this suite includes i) a modern software framework for implementing neutrino event generators, a state-of-the-art comprehensive physics model and tools to support neutrino interaction simulation for realistic experimental setups (the generator product), ii) extensive archives of neutrino, charged-lepton and hadron scattering data and software to produce a comprehensive set of data/mc comparisons (the comparisons product), and iii) a generator tuning framework and fitting applications (the tuning product). this book provides the definite guide for the genie generator: it presents the software architecture and a detailed description of its physics model and official tunes. in addition, it provides a rich set of data/mc comparisons that characterise the physics performance of genie. detailed step-by-step instructions on how to install and configure the generator, run its applications and analyze its outputs are also included. | the genie neutrino monte carlo generator: physics and user manual |
we analyze the universal radiative correction δrv to neutron and superallowed nuclear β decay by expressing the hadronic γ w -box contribution in terms of a dispersion relation, which we identify as an integral over the first nachtmann moment of the γ w interference structure function f3(0 ). by connecting the needed input to existing data on neutrino and antineutrino scattering, we obtain an updated value of δrv=0.02467 (22 ), wherein the hadronic uncertainty is reduced. assuming other standard model theoretical calculations and experimental measurements remain unchanged, we obtain an updated value of |vu d|=0.97370 (14 ), raising tension with the first row cabibbo-kobayashi-maskawa unitarity constraint. we comment on ways current and future experiments can provide input to our dispersive analysis. | reduced hadronic uncertainty in the determination of vu d |
coherent elastic neutrino-nucleus scattering consistent with the standard model has been observed by the coherent experiment. we study nonstandard neutrino interactions using the detected spectrum. for the case in which the nonstandard interactions (nsi) are induced by a vector mediator lighter than 50 mev, we obtain constraints on the coupling of the mediator. for a heavier mediator, we find that degeneracies between the nsi parameters severely weaken the constraints. however, these degeneracies do not affect coherent constraints on the effective nsi parameters for matter propagation in the earth. | coherent constraints on nonstandard neutrino interactions |
effective neutrino-quark generalized interactions are entirely determined by lorentz invariance, so they include all possible four-fermion nonderivative lorentz structures. they contain neutrino-quark nonstandard interactions as a subset, but span over a larger set that involves effective scalar, pseudoscalar, axial and tensor operators. using recent coherent data, we derive constraints on the corresponding couplings by considering scalar, vector and tensor quark currents and assuming no lepton flavor dependence. we allow for mixed neutrino-quark lorentz couplings and consider two types of scenarios in which: (i) one interaction at the nuclear level is present at a time, (ii) two interactions are simultaneously present. for scenarios (i) our findings show that scalar interactions are the most severely constrained, in particular for pseudoscalar-scalar neutrino-quark couplings. in contrast, tensor and nonstandard vector interactions still enable for sizable effective parameters. we find as well that an extra vector interaction improves the data fit when compared with the result derived assuming only the standard model contribution. in scenarios (ii) the presence of two interactions relaxes the bounds and opens regions in parameter space that are otherwise closed, with the effect being more pronounced in the scalar-vector and scalar-tensor cases. we point out that barring the vector case, our results represent the most stringent bounds on effective neutrino-quark generalized interactions for mediator masses of order ∼1 gev . they hold as well for larger mediator masses, case in which they should be compared with limits from neutrino deep-inelastic scattering data. | coherent analysis of neutrino generalized interactions |
the observation of coherent elastic neutrino nucleus scattering has opened the window to many physics opportunities. this process has been measured by the coherent collaboration using two different targets, first csi and then argon. recently, the coherent collaboration has updated the csi data analysis with a higher statistics and an improved understanding of systematics. here we perform a detailed statistical analysis of the full csi data and combine it with the previous argon result. we discuss a vast array of implications, from tests of the standard model to new physics probes. in our analyses we take into account experimental uncertainties associated to the efficiency as well as the timing distribution of neutrino fluxes, making our results rather robust. in particular, we update previous measurements of the weak mixing angle and the neutron root mean square charge radius for csi and argon. we also update the constraints on new physics scenarios including neutrino nonstandard interactions and the most general case of neutrino generalized interactions, as well as the possibility of light mediators. finally, constraints on neutrino electromagnetic properties are also examined, including the conversion to sterile neutrino states. in many cases, the inclusion of the recent csi data leads to a dramatic improvement of bounds. | physics implications of a combined analysis of coherent csi and lar data |
we compile information from low-energy observables sensitive to flavor-conserving 4-fermion operators with two or four leptons. our analysis includes data from e + e - colliders, neutrino scattering on electron or nucleon targets, atomic parity violation, parity-violating electron scattering, and the decay of pions, neutrons, nuclei and tau leptons. we recast these data as tree-level constraints on 4-fermion operators in the standard model effective field theory (smeft) where the sm lagrangian is extended by dimension-6 operators. we allow all independent dimension-6 operators to be simultaneously present with an arbitrary flavor structure. the results are presented as a multi-dimensional likelihood function in the space of dimension-6 wilson coefficients, which retains information about the correlations. in this form, the results can be readily used to place limits on masses and couplings in a large class of new physics theories. | compilation of low-energy constraints on 4-fermion operators in the smeft |
the process of neutral-current coherent elastic neutrino-nucleus scattering, consistent with the standard model (sm) expectation, has been recently measured by the coherent experiment at the spallation neutron source. on the basis of the observed signal and our nuclear calculations for the relevant cs and i isotopes, the extracted constraints on both conventional and exotic neutrino physics are updated. the present study concentrates on various sm extensions involving vector and tensor nonstandard interactions as well as neutrino electromagnetic properties, with an emphasis on the neutrino magnetic moment and the neutrino charge radius. furthermore, models addressing a light sterile neutrino state and scenarios with new propagator fields—such as vector z' and scalar bosons—are examined, and the corresponding regions excluded by the coherent experiment are presented. | coherent constraints to conventional and exotic neutrino physics |
the release of genie v3.0.0 was a major milestone in the long history of the genie project, delivering several alternative comprehensive neutrino interaction models, improved charged-lepton scattering simulations, a range of beyond the standard model simulation capabilities, improved experimental interfaces, expanded core framework capabilities, and advanced new frameworks for the global analysis of neutrino scattering data and tuning of neutrino interaction models. steady progress continued following the release of genie v3.0.0. new tools and a large number of new physics models, comprehensive model configurations, and tunes have been made publicly available and planned for release in v3.2.0. this article highlights some of the most recent technical and physics developments in the genie v3 series. | recent highlights from genie v3 |
using the coherent elastic neutrino-nucleus scattering data of the coherent experiment, we determine for the first time the average neutron rms radius of <mml:mmultiscripts>cs 133 </mml:mmultiscripts> and <mml:mmultiscripts>i 127 </mml:mmultiscripts> . we obtain the practically model-independent value rn=5.5-1.1+0.9 fm using the symmetrized fermi and helm form factors. we also point out that the coherent data show a 2.3 σ evidence of the nuclear structure suppression of the full coherence. | average csi neutron density distribution from coherent data |
the cenns-10 experiment of the coherent collaboration has recently reported the first detection of coherent-elastic neutrino-nucleus scattering (cevns) in liquid argon with more than 3σ significance. in this work, we exploit the new data in order to probe various interesting parameters which are of key importance to cevns within and beyond the standard model. a dedicated statistical analysis of these data shows that the current constraints are significantly improved in most cases. we derive a first measurement of the neutron rms charge radius of argon, and also an improved determination of the weak mixing angle in the low energy regime. we also update the constraints on neutrino non-standard interactions, electromagnetic properties and light mediators with respect to those derived from the first coherent-csi data. | implications of the first detection of coherent elastic neutrino-nucleus scattering (cevns) with liquid argon |
we calculate coherent elastic neutrino-nucleus scattering cross sections on spin-0 nuclei (e.g. 40ar and 28si) at energies below 100 mev within the standard model and account for all effects of permille size. we provide a complete error budget including uncertainties at nuclear, nucleon, hadronic, and quark levels separately as well as perturbative error. our calculation starts from the four-fermion effective field theory to explicitly separate heavy-particle mediated corrections (which are absorbed by wilson coefficients) from light-particle contributions. electrons and muons running in loops introduce a non- trivial dependence on the momentum transfer due to their relatively light masses. these same loops, and those mediated by tau leptons, break the flavor universality because of mass-dependent electromagnetic radiative corrections. nuclear physics uncertainties significantly cancel in flavor asymmetries resulting in subpercent relative errors. we find that for low neutrino energies, the cross section can be predicted with a relative precision that is competitive with neutrino-electron scattering. we highlight potentially useful applications of such a precise cross section prediction ranging from precision tests of the standard model, to searches for new physics and to the monitoring of nuclear reactors. | flavor-dependent radiative corrections in coherent elastic neutrino-nucleus scattering |
heavy neutrinos with additional interactions have recently been proposed as an explanation to the miniboone excess. these scenarios often rely on marginally boosted particles to explain the excess angular spectrum, thus predicting large rates at higher-energy neutrino-electron scattering experiments. we place new constraints on this class of models based on neutrino-electron scattering sideband measurements performed at miner ν a and charm-ii. a simultaneous explanation of the angular and energy distributions of the miniboone excess in terms of heavy neutrinos with light mediators is severely constrained by our analysis. in general, high-energy neutrino-electron scattering experiments provide strong constraints on explanations of the miniboone observation involving light mediators. | testing new physics explanations of the miniboone anomaly at neutrino scattering experiments |
coherent elastic neutrino-nucleus scattering is a powerful probe of neutrino properties, in particular of the neutrino charge radii. we present the bounds on the neutrino charge radii obtained from the analysis of the data of the coherent experiment. we show that the time information of the coherent data allows us to restrict the allowed ranges of the neutrino charge radii, especially that of νμ . we also obtained for the first time bounds on the neutrino transition charge radii, which are quantities beyond the standard model. | neutrino charge radii from coherent elastic neutrino-nucleus scattering |
motivated by the recent observation of coherent elastic neutrino-nucleus scattering (ceνns) at the coherent experiment, our goal is to explore its potential in probing important nuclear structure parameters. we show that the recent coherent data offers unique opportunities to investigate the neutron nuclear form factor. our present calculations are based on the deformed shell model (dsm) method which leads to a better fit of the recent ceνns data, as compared to known phenomenological form factors such as the helm-type, symmetrized fermi and klein-nystrand. the attainable sensitivities and the prospects of improvement during the next phase of the coherent experiment are also considered and analyzed in the framework of two upgrade scenarios. | constraining nuclear physics parameters with current and future coherent data |
the observation of coherent elastic neutrino nucleus scattering (ceνns) by the coherent collaboration in 2017 has opened a new window to both test standard model predictions at relatively low energies and probe new physics scenarios. our investigations show, however, that a careful treatment of the statistical methods used to analyze the data is essential to derive correct constraints and bounds on new physics parameters. in this manuscript we perform a detailed analysis of the publicly available coherent csi data making use of all available background data. we point out that wilks' theorem is not fulfilled in general and a calculation of the confidence regions via monte carlo simulations following a feldman-cousins procedure is necessary. as an example for the necessity of this approach to test new physics scenarios we quantify the allowed ranges for several scenarios with neutrino non-standard interactions. furthermore, we provide accompanying code to enable an easy implementation of other new physics scenarios as well as data files of our results: https://github.com/juliagehrlein/7stats. | a statistical analysis of the coherent data and applications to new physics |
recently, an improved quenching factor (qf) measurement for low-energy nuclear recoils in csi[na] has been reported by the coherent collaboration. the new energy-dependent qf is characterized by a reduced systematic uncertainty and leads to a better agreement between the experimental coherent data and the standard model (sm) expectation. in this work, we report updated constraints on parameters that describe the process of coherent elastic neutrino-nucleus scattering within and beyond the sm, and we also present how the new qf affects their interpretation. | coherent constraints after the coherent-2020 quenching factor measurement |
we present an improved determination of the strange quark and antiquark parton distribution functions of the proton by means of a global qcd analysis that takes into account a comprehensive set of strangeness-sensitive measurements: charm-tagged cross sections for fixed-target neutrino-nucleus deep-inelastic scattering, and cross sections for inclusive gauge-boson production and w-boson production in association with light jets or charm quarks at hadron colliders. our analysis is accurate to next-to-next-to-leading order in perturbative qcd where available, and specifically includes charm-quark mass corrections to neutrino-nucleus structure functions. we find that a good overall description of the input dataset can be achieved and that a strangeness moderately suppressed in comparison to the rest of the light sea quarks is strongly favored by the global analysis. | the strangest proton? |
we present a detailed study of charged-current neutrino-nucleus reactions in a fully relativistic framework and comparisons with recent experiments spanning an energy range from hundreds of mev up to 100 gev within the superscaling approach, which is based on the analysis of electron-nucleus scattering data and has been recently improved with the inclusion of relativistic mean field theory effects. we also evaluate and discuss the impact of two-particle two-hole meson-exchange currents on neutrino-nucleus interactions through the analysis of two-particle two-hole axial and vector contributions to weak response functions in a fully relativistic fermi gas. the results show a fairly good agreement with experimental data over the whole range of neutrino energies. | charged-current neutrino-nucleus reactions within the superscaling meson-exchange current approach |
we study radiative corrections to low-energy charged-current processes involving nucleons, such as neutron beta decay and (anti)neutrino-nucleon scattering within a top-down effective-field-theory approach. we first match the standard model to the low-energy effective theory valid below the weak scale and, using renormalization group equations with anomalous dimensions of o (α ,α αs,α2) , evolve the resulting effective coupling down to the hadronic scale. here, we first match to heavy-baryon chiral perturbation theory and subsequently, below the pion-mass scale, to a pionless effective theory, evolving the effective vector coupling with anomalous dimensions of o (α ,α2) all the way down to the scale of the electron mass, relevant for beta decays. we thus provide a new evaluation of the "inner" radiative corrections to the vector coupling constant and to the neutron decay rate, discussing differences with the previous literature. using our new result for the radiative corrections, we update the extraction of the cabibbo-kobayashi-maskawa matrix element vu d from the neutron decay. | effective field theory for radiative corrections to charged-current processes: vector coupling |
we formulate an effective field theory (eft) for non standard neutrino interactions (nsi) in elastic scattering with light quarks, leptons, gluons and photons, including all possible operators of dimension 5, 6 and 7. we provide the expressions for the cross sections in coherent neutrino-nucleus scattering and in deep inelastic scattering. assuming single operator dominance we constrain the respective wilson coefficient using the measurements by the coherent and charm collaborations. we also point out the constraining power of future elastic neutrino-nucleus scattering experiments. finally, we explore the implications of the bounds for smeft operators above the electroweak breaking scale. | non-standard neutrino interactions and low energy experiments |
we illustrate the connection between electron and neutrino scattering off nuclei and show how the former process can be used to constrain the description of the latter. after reviewing some of the nuclear models commonly used to study lepton-nucleus reactions, we describe in detail the susav2 model and show how its predictions compare with the available electron- and neutrino-scattering data over the kinematical range going from the quasi-elastic peak to pion-production and highly inelastic scattering. | electron- versus neutrino-nucleus scattering |
we present the first calculation of the hadronic tensor on the lattice for the nucleon. the hadronic tensor can be used to extract structure functions in deep inelastic scatterings and to provide information for neutrino-nucleon scattering which is crucial to neutrino-nucleus scattering experiments at low energies. the most challenging part in the calculation is to solve an inverse problem. we have implemented and tested three algorithms using mock data, showing that the bayesian reconstruction method has the best resolution in extracting peak structures while the backus-gilbert and maximum entropy methods are somewhat more stable for smooth functions. numerical results are presented for both the elastic case (clover fermions on domain wall configurations with mπ∼370 mev and a ∼0.06 fm ) and a case (anisotropic clover lattice with mπ∼380 mev and at∼0.035 fm ) with large momentum transfer. for the former case, the reconstructed minkowski hadronic tensor gives precisely the vector charge which proves the feasibility of the approach. for the latter case, the resonance and possibly shallow inelastic scattering contributions around energy transfer ν =1 gev are clearly observed but no information is obtained for higher excited states with ν >2 gev . a check of the effective masses of the ρ meson with different lattice setups indicates that, in order to reach higher energy transfers, using lattices with smaller lattice spacings is essential. | towards the nucleon hadronic tensor from lattice qcd |
the dynamic linear response of a quantum system is critical for understanding both the structure and dynamics of strongly interacting quantum systems, including neutron scattering from materials, photon and electron scattering from atomic systems, and electron and neutrino scattering by nuclei. we present a general algorithm for universal quantum computers to calculate the dynamic linear response function with controlled errors and to obtain information about specific final states that can be directly compared to experimental observations. | dynamic linear response quantum algorithm |
using the new results on coherent elastic neutrino-nucleus scattering data in cesium-iodide provided by the coherent experiment, we determine a new measurement of the average neutron rms radius of 133cs and 127i. in combination with the atomic parity violation (apv) experimental result, we derive the most precise measurement of the neutron rms radii of 133cs and 127i, disentangling for the first time the contributions of the two nuclei. by exploiting these measurements we determine the corresponding neutron skin values for 133cs and 127i. these results suggest a preference for models which predict large neutron skin values, as corroborated by the only other electroweak measurements of the neutron skin of 208pb performed by prex experiments. moreover, for the first time, we obtain a data-driven apv+coherent measurement of the low-energy weak mixing angle with a percent uncertainty, independent of the value of the average neutron rms radius of 133cs and 127i, that is allowed to vary freely in the fit. the value of the low-energy weak mixing angle that we found is slightly larger than the standard model prediction. | new insights into nuclear physics and weak mixing angle using electroweak probes |
we present new sets of nuclear parton distribution functions (npdfs) at next-to-leading order and next-to-next-to-leading order. our analyses are based on deeply inelastic scattering data with charged-lepton and neutrino beams on nuclear targets. in addition, a set of proton baseline pdfs is fitted within the same framework with the same theoretical assumptions. the results of this global qcd analysis are compared to existing npdf sets and to the fitted cross sections. also, the uncertainties resulting from the limited constraining power of the included experimental data are presented. the published work is based on an open-source tool, xuc(f)itter, which has been modified to be applicable also for a nuclear pdf analysis. the required extensions of the code are discussed as well. | open-source qcd analysis of nuclear parton distribution functions at nlo and nnlo |
coherent elastic neutrino scattering on the 40ar nucleus is computed with coupled-cluster theory based on nuclear hamiltonians inspired by effective field theories of quantum chromodynamics. our approach is validated by calculating the charge form factor and comparing it to data from electron scattering. we make predictions for the weak form factor, the neutron radius, and the neutron skin and estimate systematic uncertainties. the neutron-skin thickness of 40ar is consistent with results from density-functional theory. precision measurements from coherent elastic neutrino-nucleus scattering could potentially be used to extract these observables and help to constrain nuclear models. | coherent elastic neutrino-nucleus scattering on 40ar from first principles |
we compare recent minerva antineutrino-hydrogen charged-current measurements to phenomenological predictions of the axial-vector form factor based on fits to all available electron scattering and deuterium bubble-chamber data and to representative lattice-qcd (lqcd) determination by the pndme collaboration. while there is 1 σ - 2 σ agreement in the cross section with minerva data for each bin in q2, we identify three regions with different relevance and opportunity for lqcd predictions. for q2≲0.2 gev2, the phenomenological extractions have large number of data points and lqcd is competitive, while minerva data have large errors. for 0.2 gev2≲q2≲1 gev2, lqcd is competitive with the minerva determination, and both give values larger than from phenomenological extraction. for q2>1 gev2, the minerva data are the most precise. our analysis indicates that with improving precision of minerva-like experiments and lqcd data, the uncertainty in the nucleon axial-vector form factor will be steadily reduced. | confronting the axial-vector form factor from lattice qcd with minerva antineutrino-proton data |
we present an updated analysis of the coherent neutrino-nucleus elastic scattering data of the coherent experiment, taking into account the new quenching factor published recently in [phys. rev. d 100, 033003 (2019), 10.1103/physrevd.100.033003]. through a fit of the coherent time-integrated energy spectrum, we show that the new quenching factor leads to a better determination of the average rms radius of the neutron distributions of 133cs and 127i, while in combination with the atomic parity violation (apv) experimental results, it allows us to determine a data-driven apv measurement of the low-energy weak mixing angle in very good agreement with the standard model prediction. we also find a 3.7 σ evidence of the suppression of coherence due to the nuclear structure. neutrino properties are better constrained by considering the coherent time-dependent spectral data, that allow us to improve the bounds on the neutrino charge radii and magnetic moments. we also present for the first time constraints on the neutrino charges obtained with coherent neutrino-nucleus elastic scattering data. in particular, we obtain the first laboratory constraints on the diagonal charge of νμ and the νμ-ντ transition charge. | neutrino, electroweak, and nuclear physics from coherent elastic neutrino-nucleus scattering with refined quenching factor |
in the presence of transition magnetic moments between active and sterile neutrinos, the search for a primakoff upscattering process at coherent elastic neutrino-nucleus scattering (ce ν ns ) experiments can provide stringent constraints on the neutrino magnetic moment. we show that a radiative upscattering process with an emitted photon in the final state can induce a novel coincidence signal at ce ν ns experiments that can also probe neutrino transition magnetic moments beyond existing limits. furthermore, the differential distributions for such a radiative mode can also potentially be sensitive to the dirac vs majorana nature of the sterile state mediating the process. this can provide valuable insights into the nature and mass generation mechanism of the light active neutrinos. | probing active-sterile neutrino transition magnetic moments with photon emission from ce ν ns |
we carry out an ab initio calculation of the neutrino flux-folded inclusive cross sections measured on 12c by the miniboone and t2k collaborations in the charged-current quasielastic regime. the calculation is based on realistic two- and three-nucleon interactions, and on a realistic nuclear electroweak current with one- and two-nucleon terms that are constructed consistently with these interactions and reproduce low-energy electroweak transitions. numerically exact quantum monte carlo methods are utilized to compute the nuclear weak response functions, by fully retaining many-body correlations in the initial and final states and interference effects between one- and two-body current contributions. we employ a nucleon axial form factor of the dipole form with λa=1.0 or 1.15 gev, the latter more in line with a very recent lattice qcd determination. the calculated cross sections are found to be in good agreement with the neutrino data of miniboone and t2k, and antineutrino miniboone data, yielding a consistent picture of nuclei and their electroweak properties across a wide regime of energy and momenta. | ab initio study of (νℓ,ℓ-) and (ν¯ℓ,ℓ+) inclusive scattering in 12c: confronting the miniboone and t2k ccqe data |
the neutrino-electron scattering process is a powerful tool to explore new physics beyond the standard model. recently the possibility of dune near detector (nd) to constrain various new physics scenarios using this process have been highlighted in the literature. in this work, we consider the most general u(1) model and probe the constraints on the mass and coupling strength of the additional z' from ν - e scattering at dune nd. the presence of the z' gives rise to extra interference effects. in the context of the general u(1) model, the destructive interference can occur in either neutrino or anti-neutrino channel or for both or none. this opens up the possibilities of getting four different type of signal in the neutrino and ant-neutrino runs of dune. we perform the analysis using both the total rate and binned events spectrum. our results show that in a bin by bin analysis the effect of destructive interference is less compared to the analysis using total rate. we present the bounds on the mz'- gx plane from ν - e scattering measurements at dune nd and compare these with those obtained from other ν - e scattering, coherent, and beam dump experiments. we show that the dune nd can give the best bound for certain mass ranges of z'. | constraining general u(1) interactions from neutrino-electron scattering measurements at dune near detector |
we investigate the impact of a fourth sterile neutrino at reactor and spallation neutron source neutrino detectors. specifically, we explore the discovery potential of the texono and coherent experiments to subleading sterile neutrino effects through the measurement of the coherent elastic neutrino-nucleus scattering event rate. our dedicated χ2-sensitivity analysis employs realistic nuclear structure calculations adequate for high purity sub-kev threshold germanium detectors. | probing light sterile neutrino signatures at reactor and spallation neutron source neutrino experiments |
a new measurement of the quenching factor for low-energy nuclear recoils in csi[na] is presented. past measurements are revisited, identifying and correcting several systematic effects. the resulting global data are well described by a physics-based model for the generation of scintillation by ions in this material, in agreement with phenomenological considerations. the uncertainty in the new model is reduced by a factor of four with respect to an energy-independent quenching factor initially adopted as a compromise by the coherent collaboration. a significantly improved agreement with standard model predictions for the first measurement of coherent elastic neutrino-nucleus scattering (ceνns) is generated. we emphasize the critical impact of the quenching factor on the search for new physics via ceνns experiments. | response of csi[na] to nuclear recoils: impact on coherent elastic neutrino-nucleus scattering |
we review current standard and non-standard neutrino physics probes that are based on nuclear measurements. we pay special attention on the discussion of prospects to extract new physics at prominent rare event measurements looking for neutrino-nucleus scattering, as the coherent elastic neutrino-nucleus scattering that may involve lepton flavour violation (lfv) in neutral currents (nc). for the latter processes several appreciably sensitive experiments, like the coherent, miner, conus, texono, red100 and others, using promising target nuclei are in operation or have been planed to operate in the near future. we also discuss comprehensively phenomenological and theoretical studies, in particular those referred to the nuclear physics aspects and provide useful predictions for the relevant experiments. furthermore, motivated by the recent discovery of ceνns at the coherent experiment, we summarize the impact of non-standard interactions and novel vector z^\prime or scalar φ mediators to the ceνns event rates and provides estimates for the corresponding current and future sensitivities. | recent probes of standard and non-standard neutrino physics with nuclei |
after the first measurement of the coherent elastic neutrino nucleus scattering (cenns) by the coherent collaboration, it is expected that new experiments will confirm the observation. such measurements will allow to put stronger constraints or discover new physics as well as to probe the standard model by measuring its parameters. this is the case of the weak mixing angle at low energies, which could be measured with an increased precision in future results of cenns experiments using, for example, reactor antineutrinos. in this work we analyze the physics potential of different proposals for the improvement of our current knowledge of this observable and show that they are very promising. | future perspectives for a weak mixing angle measurement in coherent elastic neutrino nucleus scattering experiments |
we analyze the universal radiative correction $\delta_r^v$ to neutron and superallowed nuclear $\beta$ decay by expressing the hadronic $\gamma w$-box contribution in terms of a dispersion relation, which we identify as an integral over the first nachtmann moment of the $\gamma w$ interference structure function $f_3^{(0)}$. by connecting the needed input to existing data on neutrino and antineutrino scattering, we obtain an updated value of $\delta_r^v = 0.02467(22)$, wherein the hadronic uncertainty is reduced. assuming other standard model theoretical calculations and experimental measurements remain unchanged, we obtain an updated value of $|v_{ud}| = 0.97366(15)$, raising tension with the first row ckm unitarity constraint. we comment on ways current and future experiments can provide input to our dispersive analysis. | reduced hadronic uncertainty in the determination of $v_{ud}$ |
coherent elastic neutrino-nucleus scattering (ceν ns ) offers a unique way to study neutrino properties and to search for new physics beyond the standard model. nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few mev. in this paper, a new-generation experiment to study ceν ns is described. the nucleus experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring ceν ns of reactor anti-neutrinos. a new experimental site, the very-near-site (vns), at the chooz nuclear power plant in france is described. the vns is located between the two 4.25 gwth reactor cores and matches the requirements of nucleus. first results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. in this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. the paper concludes with a sensitivity study pointing out the physics potential of nucleus at the chooz nuclear power plant. | exploring ceν ns with nucleus at the chooz nuclear power plant |
using the first model independent average neutron rms radius of 133cs and 127i obtained from the analysis of the coherent elastic neutrino-nucleus scattering data of the coherent experiment, we show the effect on the weak mixing angle measurement from the atomic parity violation (apv) in cesium. despite that the large uncertainty on the neutron skin measurement makes it difficult to draw statistically significant conclusions on the weak mixing angle, we exploit the fact that the apv result is highly sensitive to the cesium neutron rms radius, rn, to combine the apv and the coherent measurements in order to get a better determination of rn, assuming that the standard model is correct. the value of rn=5.42 ±0.31 fm is obtained, improving significantly the current uncertainty. this result allows to infer a meaningful value of the cesium neutron skin, the difference between the neutron and proton distribution radii, equal to δ rn p=0.62 ±0.31 fm , showing for the first time a 2 σ deviation from zero. | reinterpreting the weak mixing angle from atomic parity violation in view of the cs neutron rms radius measurement from coherent |
we have presented a review of the properties of neutrinos and their interactions with matter. the different (anti)neutrino processes like the quasielastic scattering, inelastic production of mesons and hyperons, and the deep inelastic scattering from the free nucleons are discussed, and the results for the scattering cross sections are presented. the polarization observables for the leptons and hadrons produced in the final state, in the case of quasielastic scattering, are also studied. the importance of nuclear medium effects in the low, intermediate, and high energy regions, in the above processes along with the processes of the coherent neutrino-nucleus scattering, coherent meson production, and trident production, has been highlighted. in some cases, the results of the cross sections are also given and compared with the available experimental data as well as with the predictions in the different theoretical models. this study would be helpful in understanding the (anti)neutrino interaction cross section with matter in the few gev energy region relevant to the next generation experiments like dune, hyper-kamiokande, and other experiments with accelerator and atmospheric neutrinos. we have emphasized the need of better theoretical models for some of these processes for studying the nuclear medium effects in nuclei. | neutrinos and their interactions with matter |
the formalism based on factorization and nuclear spectral functions has been generalized to treat transition matrix elements involving two-nucleon currents, whose contribution to the nuclear electromagnetic response in the transverse channel is known to be significant. we report the results of calculations of the inclusive electron-carbon cross section, showing that the inclusion of processes involving two-nucleon currents appreciably improves the agreement between theory and data in the dip region, between the quasielastic and δ -production peaks. the relation to approaches based on the independent particle of the nucleus and the implications for the analysis of flux-integrated neutrino-nucleus cross sections are discussed. | unified description of electron-nucleus scattering within the spectral function formalism |
we present the constraints on the parameters of several light boson mediator models obtained from the analysis of the current data of the coherent ce$\nu$ns experiment. we consider a variety of vector boson mediator models: the so-called universal, the $b-l$ and other anomaly-free $u(1)'$ gauge models with direct couplings of the new vector boson with neutrinos and quarks, and the anomaly-free $l_e-l_\mu$, $l_e-l_\tau$, and $l_\mu-l_\tau$ gauge models where the coupling of the new vector boson with the quarks is generated by kinetic mixing with the photon at the one-loop level. we consider also a model with a new light scalar boson mediator that is assumed, for simplicity, to have universal coupling with quarks and leptons. since the coherent ce$\nu$ns data are well-fitted with the cross section predicted by the standard model, the analysis of the data yields constraints for the mass and coupling of the new boson mediator that depend on the charges of quarks and neutrinos in each model under consideration. we compare these constraints with the limits obtained in other experiments and with the values that can explain the muon $g-2$ anomaly in the models where the muon couples to the new boson mediator. | probing light mediators and $(g-2)_{\\mu}$ through detection of coherent elastic neutrino nucleus scattering at coherent |
release of coherent collaboration data from the first detection of coherent elastic neutrino-nucleus scattering (cevns) on argon. this release corresponds with the results of "analysis a" published in akimov et al., arxiv:2003.10630 [nucl-ex]. data is shared in a binned, text-based format representing both "signal" and "backgrounds" along with associated uncertainties such that the included data can be used to perform independent analyses. this document describes the contents of the data release as well as guidance on the use of the data. included example code in c++ (root) and python show one possible use of the included data. | coherent collaboration data release from the first detection of coherent elastic neutrino-nucleus scattering on argon |
we report the results of a theoretical study of quasielastic electron and neutrino interactions with carbon. our approach takes into account the effects of final-state interactions between the struck nucleon and the residual nucleus, neglected in the impulse approximation, through a generalization of the spectral function formalism. the calculated electron-scattering cross sections turn out to be in very good agreement with the available data over a broad kinematical region. the impact of nuclear effects on the reconstruction of neutrino energy in charged-current quasielastic processes is also studied, and the results of our approach are compared to the predictions of the relativistic fermi gas model, routinely employed in most monte carlo simulations. finally, we discuss the limitations of the existing procedure for energy reconstruction and propose a new, improved, one. at energy ∼600 mev , we observe a sizable difference between neutrino and antineutrino scattering, important for the measurements of charge-parity symmetry violation. our analysis suggests that a reliable determination of neutrino energy can only be obtained from models validated by a systematic comparison to the available electron-scattering data. | improving the accuracy of neutrino energy reconstruction in charged-current quasielastic scattering off nuclear targets |
coherent elastic neutrino-nucleus scattering (cevns) is a standard model process that, although predicted for decades, has only been detected recently by the coherent collaboration. now that cevns has been discovered, it provides a new probe for physics beyond the standard model. we study the potential to probe new physics with cevns through the use of low temperature bolometers at a reactor source. we consider contributions to cevns due to a neutrino magnetic moment (nmm), non-standard interactions (nsi) that may or may not change flavor, and simplified models containing a massive scalar or vector mediator. targets consisting of ge, zn, si, cawo4, and al2o3 are examined. we show that by reaching a percentage-level precision measurement on the cevns energy spectrum down to script o(10) ev, forthcoming experiments will improve by two orders of magnitude both the cevns-based nmm limit and the search for new massive mediators. additionally, we demonstrate that such dedicated low-threshold cevns experiments will lead to unprecedented constraints on nsi parameters (particularly when multiple targets are combined) which will have major implications for the global neutrino physics program. | prospects for exploring new physics in coherent elastic neutrino-nucleus scattering |
in this work we study the current bounds from the ceνns process and meson invisible decays on generic neutrino interactions with sterile neutrinos in effective field theories. the interactions between quarks and left-handed sm neutrinos and/or right-handed neutrinos are first described by the low-energy effective field theory (lneft) between the electroweak scale and the chiral symmetry breaking scale. we complete the independent operator basis for the lneft up to dimension-6 by including both the lepton-number-conserving (lnc) and lepton-number-violating (lnv) operators involving right-handed neutrinos. we translate the bounds on the lneft wilson coefficients from the coherent observation and calculate the branching fractions of light meson invisible decays. the bounds on lneft are then mapped onto the sm effective field theory with sterile neutrinos (smneft) to constrain new physics above the electroweak scale. we find that the meson invisible decays can provide the only sensitive probe for τ neutrino flavor component and s quark component in the quark-neutrino interactions involving two (one) active neutrinos and for the effective operators without any active neutrino fields. the ceνns process places the most stringent bound on all other wilson coefficients. by assuming one dominant wilson coefficient at a time in smneft and negligible sterile neutrino mass, the most stringent limits on the new physics scale are 2.7-10 tev from corresponding dipole operator in lneft and 0.5-1.5 tev from neutrino-quark operator in lneft. | general neutrino interactions with sterile neutrinos in light of coherent neutrino-nucleus scattering and meson invisible decays |
using an effective field theory approach, we study coherent neutrino scattering on nuclei, in the setup pertinent to the coherent experiment. we include non-standard effects both in neutrino production and detection, with an arbitrary flavor structure, with all leading wilson coefficients simultaneously present, and without assuming factorization in flux times cross section. a concise description of the coherent event rate is obtained by introducing three generalized weak charges, which can be associated (in a certain sense) to the production and scattering of νe, νμ and ν¯μ on the nuclear target. our results are presented in a convenient form that can be trivially applied to specific new physics scenarios. in particular, we find that existing coherent measurements provide percent level constraints on two combinations of wilson coefficients. these constraints have a visible impact on the global smeft fit, even in the constrained flavor-blind setup. the improvement, which affects certain 4-fermion llqq operators, is significantly more important in a flavor-general smeft. our work shows that coherent data should be included in electroweak precision studies from now on. | eft analysis of new physics at coherent |
achieving a percentage-level precision measurement of the coherent elastic neutrino nucleus scattering (ceν ns) spectrum requires a robust data processing pipeline which can be characterised with great precision. to fulfil this goal, we present hereafter a new python-based data processing pipeline specifically designed for temporal data analysis and pulse amplitude estimation. this pipeline features a data generator allowing to accurately simulate the expected data stream from the ricochet experiment at the institut laue langevin nuclear reactor, including both background and ceν ns signals. this data generator is pivotal to fully understand and characterise the data processing overall efficiency, its reconstruction biases, and to properly optimise its configuration parameters. we show that thanks to this optimised data processing pipeline, the cryocube detector array will be able to achieve a 70 ev energy threshold combined with electronic/nuclear recoil discrimination down to ∼100 ev, hence fulfilling the ricochet targeted performance. | development of data processing and analysis pipeline for the ricochet experiment |
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