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a combination of nuv and optical imaging of m82, the nearest star-bursting galaxy, allows us to probe the properties of the dust, both in the interstellar medium of the galaxy, as well as the dust entrained in the extraplanar gas blown by the super wind. we compare the photometric observations with sets of population s... | a panchromatic view of m82: dust properties |
we compute libraries of stellar + nebular spectra of populations of coeval stars with ages of <100 myr and metallicities of z=0.001 to 0.040, using different sets of massive-star evolution tracks, i.e., new padova tracks for single non-rotating stars, the geneva tracks for single non-rotating and rotating stars, and... | photometrically-derived properties of massive-star clusters obtained with different massive-star evolution tracks and deterministic models |
massive luminous red galaxies (lrgs) are believed to be evolving passively and can be used as cosmic chronometers to estimate the hubble constant (the differential age method). however, different lrgs may locate in different environments and the environment effects may affect the accuracies of the measurements of both ... | ``quiescent'' luminous red galaxies (lrgs) as cosmic chronometers: on the significance of the mass and environmental dependence of lrgs |
ultra-luminous x-ray sources are among the most extreme phases of binary evolution, characterized by x-ray luminosities exceeding 1e39 erg/s (approximately the eddington limit for a stellar mass black hole). the recent discovery of a neutron star accretor in the ultra-luminous x-ray source m82 x-2 challenges our unders... | on the formation of ultraluminous x-ray sources with neutron star accretors: the case of m82 x-2 |
as the former envelopes of evolved stars, planetary nebulae (pne) present an opportunity to study slow neutron-capture reactions (the “s-process”) during the agb. such studies differ from those of agb stars in two ways. first, pne represent the end point of self-enrichment and dredge-up in the star and most of its mass... | observing infrared emission lines of neutron-capture species in planetary nebulae: new detections with igrins |
detached white dwarf + main sequence (wd+ms) systems represent the simplest population of post-common envelope binaries (pcebs), and their ensemble properties carry important information about common-envelope phase. however, most population synthesis studies do not fully consider the effects of the observational select... | a population synthesis study of the ms+wd population in the sdss |
we present a new medium resolution (full width at half-maximum fwhm ~ 2.4 å) spectral library containing 1903 stellar spectra with a wavelength coverage of 3800-9000 å based on miles spectral library which contains 985 blue arm spectra with wavelength coverage of 3500-7500 å at a spectral resolution of 2.5 å (fwhm). th... | expand miles spectral library for lamost stellar parameter determination using chinese 2.4 and 2.16 metereter telescopes |
many hot jupiter systems exhibit misalignment between the orbital axis of the planet and the spin axis of its host star. while this misalignment could be primordial in nature, a large fraction of hot jupiters are found in systems with distant stellar companions, and thus could have undergone lidov-kozai (lk) oscillatio... | spin-orbit coupling and the production of misaligned hot jupiters via lidov-kozai oscillations |
we present a sample of synthetic images of simulated galaxies and their stellar haloes from the illustris volume, a cosmological gravity+hydrodynamics simulation which has been shown to reproduce many observational constraints on the galaxy population and gas content of the universe at z=0. based on the properties of t... | the illustris simulation overview: mock observations of galaxies and their stellar haloes |
gj832 (hd 204961) is a nearby m1 v host star with two exoplanets: a jovian mass planet and a super-earth. we have obtained near-uv and far-uv spectra of gj832 with the stis and cos instruments on hst as part of the cycle 19 muscles pilot program (france et al. 2013). our objective is to obtain the first accurate physic... | an empirically-derived non-lte xuv-visible spectral synthesis model of the m1 v exoplanet host star gj832 |
high-quality stellar spectra are in great demand now - they are the most important ingredient in the stellar population synthesis to study galaxies and star clusters. here we describe the procedures to increase the quality of flux calibration of stellar spectra. we use examples of nir intermediate-resolution echelle sp... | multi-segment and echelle stellar spectra processing issues and how to solve them |
as the lowest-mass products of star formation, brown dwarfs are essential to understanding the history of our galaxy. to this end, a complete volume-limited sample of brown dwarfs in the solar neighborhood is critical for testing formation theories. to create such a sample, our hawaii infrared parallax program has rece... | the initial mass function and birth history of brown dwarfs in the solar neighborhood from a volume-limited sample |
the interstellar medium is the principal ingredient for star formation and hence, it is necessary to study the properties of the interstellar medium. radio sources in our galaxy and beyond can be used as a probe of the intervening medium. in this dissertation, i present an attempt to use radio transients like pulsars a... | radio transients and their environments |
we compare the evolution of binary systems evolved in the mesa stellar evolution code to those in the cosmic population synthesis code. our aim is to: 1) convey the robustness of the equations that model binary evolution in the cosmic code, particularly for the cases of high mass stars with closely orbiting compact obj... | understanding binary systems - a comparison between cosmic and mesa |
since its discovery, the multiple population phenomenon is an enigma in the field of stellar populations. we propose combined spectroscopic and photometric jwst observations that will finally solve this long-standing issue. so far, two competing scenarios are available: 1) multiple bursts of star formation; 2) accretio... | solving the globular clusters multiple population enigma through jwst |
the ir emission from galaxies is a unique window into multiple aspects of galaxy evolution including star-formation rates, the age of galaxies, and galactic-scale dust processes. however, asymptotic giant branch (agb) stars continue to introduce uncertainty into stellar population synthesis (sps) models and limit our a... | circumstellar dust around agb stars and implications for infrared emission from galaxies |
we present the full results of our decade-long astrometric monitoring programs targeting 31 ultracool binaries with component spectral types m7-t5. joint analysis of resolved imaging from keck and hst and unresolved astrometry from cfht/wircam yields parallactic distances for all systems, robust orbit determinations fo... | individual dynamical masses of ultracool dwarfs |
our knowledge of the formation and early evolution of globular clusters (gcs) has been totally shaken with the discovery of the peculiar chemical properties of their long-lived host stars. therefore, the interpretation of the observed colour magnitude diagrams (cmd) and of the properties of the gc stellar populations r... | globular clusters and the evolution of their multiple stellar populations |
some major uncertainties in the determination of the evolutionary status of unresolved old stellar populations, using stellar population synthesis models, are presented and discussed. it transpires that the unknown hb morphology of the target populations is a major potential source of error, together with the effect of... | uncertainties in determining the evolutionary status of unresolved old populations |
anisotropic nanomaterials, including zero-dimensional metallic nanoparticles (mnps), one-dimensional single-walled carbon nanotubes (swcnts), and two-dimensional few-layer black phosphorous (fl-p) exhibit interesting structure-dependent properties that could be exploited in biomedicine, plasmonics, and optoelectronics.... | monodisperse multidimensional nanostructures via centrifugal separation |
over much of the initial mass function, stars lose a significant fraction of their mass through a stellar wind during the late stages of their evolution when being a (super)giant star. as of today, we can not yet predict the mass-loss rate during the (super)giant phase for a given star with specific stellar parameters ... | mass-loss rates of cool stars |
stars, and collections of stars, encode rich signatures of stellar physics and galaxy evolution. with properties influenced by both their environment and intrinsic nature, stars retain information about astrophysical phenomena that are not otherwise directly observable. in the time-domain, the observed brightness varia... | decoding starlight with big survey data, machine learning, and cosmological simulations |
studies of extagalactic x-ray binary populations have shown that the characteristics of these populations depend strongly on the characteristics of the host galaxy's parent stellar population (e.g. star-formation history and metallicity). these dependencies not only make x-ray binaries promising for aiding in the measu... | accreting binary population synthesis and feedback prescriptions |
we have analyzed broadband hst photometry available to study the brightest cluster galaxies (bcgs) in x-ray luminous clusters of galaxies. these galaxies span a redshift interval of 0.152 < z < 0.55 and were identified by the canadian cluster comparison project. we used this sample to build a robust analysis pipe... | measuring stellar masses of the brightest cluster galaxies in x-ray luminous galaxy clusters using hubble space telescope archival data |
we present a population synthesis study of the cooling sequence of the globular cluster 47 tucanae. we study the distribution of effective temperatures, the morphology of the color-magnitude diagram, and the magnitude and color distributions. we find that our simulations are in very good agreement with the observationa... | a population synthesis study of the white dwarf cooling sequence of 47 tucanae |
the vast majority of stars will end their lives as white dwarfs, earth-sized electron-degenerate stars. as part of close binaries, white dwarfs give rise to a wide range of spectacular phenomena, including accretion disc instabilities, explosive shell burning, and their total annihilation in type ia supernovae. due to ... | population studies of single and binary white dwarfs |
robustly measuring the specific star formation rate in galaxies -- the star formation rate per unit stellar mass -- is crucial to understanding galaxy evolution over cosmic time. future missions, such as the james webb space telescope (jwst) and the wide field infrared space telescope (wfirst) will observe the stellar ... | recovering specific star formation rate of simulated galaxies with spectral energy density fitting |
the recent ligo/virgo detections of gravitational waves (gws) from merging bhs and nss have prompted a resurgence in efforts to self-consistently model close binary populations and their evolution. x-ray binaries (xrbs) provide an important benchmark for such efforts, and scaling relations between high-mass xrb (hmxb) ... | x-ray binary population constraints in nearby galaxies from 20 years of chandra data |
nuclear starburst discs (nsds) are very compact star-forming regions in the centres of galaxies that have been studied as a possible origin for the absorbing gas around a central active galactic nucleus. nsds may be most relevant at z ∼ 1 when obscured accretion on to supermassive black holes (smbhs) is common. this pa... | the stellar remnants of high-redshift nuclear starburst discs: a potential origin for nuclear star clusters? |
until the late sixties our knowledge about star evolution essentially rested on the hr diagram of open and globular clusters. already in the seventies, the early studies with the 40-cm objective prism astrograph at la silla revealed some striking population differences between the smc, lmc and milky way, as a result of... | contributions of la silla instruments to our understanding of stars |
with the detection of compact-object mergers with ligo/virgo there is a resurgence in modeling efforts to understand the evolution of interacting close binaries, including x-ray binaries (xrbs). critical high-value empirical constraints on this effort can be gained by xrb x-ray luminosity functions (xlfs), which provid... | new x-ray binary scaling relations in the local universe based on subgalactic modeling |
in the stellar atmospheres, radiative energy transport is dominated by only the strongest spectral lines. for these lines, the approximation of local thermo-dynamic equilibrium (lte) is known to be very inaccurate, and a state of equilibrium cannot be assumed in general. therefore to understand the structure and dynami... | non-equilibrium equation-of-state in stellar atmospheres |
the initial mass function (imf) represents the distribution of stellar masses of stars formed in one star formation event and is one of the most crucial ingredients to understand the formation and evolution of stellar populations and galaxies. we use flexible stellar population synthesis (fsps) to study the impact of f... | the impact of the initial mass function on the evolution of m/l |
using updated full-spectrum stellar population synthesis (sps) models, we present the first detailed stellar population analysis of m87 and its globular cluster (gc) system from spectroscopy. we applied the models to 322 gcs extending from the inner to outer halo. in villaume+ (2019apj...879...45v) we applied full-spec... | vizier online data catalog: new m87 gcs metallicities from keck & mmt sp. (villaume+, 2020) |
the next-generation network of gravitational wave observatories are expected to detect many more compact object mergers inside their host galaxies. in light of this future circumstances, i developed a theoretical tool that investigates the properties of formation and host galaxies of compact objects. the starting point... | the evolution of compact object mergers and their host galaxies across cosmic time |
the understanding of how, which, where and when stars form provides important information for the vast majority of astronomical fields. star-formation has a complex multi-scale physical nature. stars form in dense sub-parsec regions of molecular clouds, and since the very early stages of their life, their destiny is li... | stellar populations in gravitationally bound systems |
star formation (sf) tracers in the optical spectral range are considerably well known nowadays and had been used to identify sf in galaxies over the years. the near-infrared (nir) regime, on the other hand, remains poorly explored, even though this is an important wavelength range which is less affected by dust obscura... | a panchromatic study of the stellar populations in ngc 4303 |
the epoch of reionization (eor) was a period in the universe's history wherein the wholly neutral igm was ionized by the rapidly evolving ionizing background. due to the high opacity of the igm during this epoch, studying this period is difficult, yet it could reveal much about the traits of early galaxies. in this dis... | investigating trends in the cgm and igm during reionization |
the human pathogenic bacteria bacillus cereus, bacillus anthracis and the entomopathogenic bacillus thuringiensis form spores encased in a protein coat surrounded by a balloon-like exosporium. these structures mediate spore interactions with its environment, including the host immune system, control the transit of mole... | a new fluorescence-based approach for direct visualization of coat formation during sporulation in bacillus cereus |
in recent years, high resolution multi-object spectroscopy has enabled the measurement of detailed chemical compositions for tens to hundreds of thousands of stars in the milky way's oldest stellar populations. globular clusters and the galactic bulge have been a particular target of interest, and the accurate spectros... | insights into globular clusters and bulge field stars with moog |
the favored core accretion model of planet formation predicts a deficit of planets between the masses of neptune and saturn. this planet desert is a consequence of the runaway gas accretion process, which is thought to cause protoplanetary cores of about 10 earth masses to rapidly grow to ~300 earth masses rapidly thro... | microlensing results challenge the core accretion run-away growth scenario for gas giants |
using stellar population synthesis, we construct a model for the distribution of high-redshift galaxies on the uvj diagram, i.e. the rest-frame u-v vs v-j plane. we find that stochastic star formation history models are able to reproduce the observed color distributions of star-forming galaxies, when combined with the ... | modeling galaxy colors with stochastic star formation histories |
there appears to be correlations between sn ia hubble diagram residuals and host galaxy mass, metallicity, and star formation history. an uncorrected bias may produce a systematic offset in cosmological measurements. rigault et al. (2013) found that the local environment can correlate with hubble residuals and possibly... | correlations between hubble residuals and local stellar populations of type ia supernovae |
the ir emission from galaxies is a unique window into multiple aspects of galaxy evolution including star-formation rates, the age of galaxies, and galactic-scale dust processes. however, asymptotic giant branch (agb) stars continue to introduce uncertainty into stellar population synthesis (sps) models and limit our a... | implications of including agb dust in sps models |
introduction:in recent years, we witnessed increasing numbers of migrants worldwide owing to famine, poverty, regional conflicts,etc.efforts by the united nations and various organizations to help these migrants are hampered by rising anti-migrant sentiments and xenophobic rhetoric in many parts of the world. to arrive... | scientific debate on human migration: ethics, challenges, and solutions |
redback (rb) and black widow (bw) systems are compact binaries containing a millisecond pulsar (msp) and a low-mass stellar companion. for rbs, this companion is usually around 0.1-0.4 solar masses, while bw companions are <0.1 but tend to be a few percent of a solar mass. radio eclipses are a defining feature for m... | cosmic arachnology: ongoing studies of redback and black widow pulsars |
researchers have reanalyzed nearly 10,000 light curves from the optical gravitational lensing experiment. the resulting catalog, which is publicly available, provides new opportunities to study black holes, exoplanets, and much more.making sense of microlensingan illustration of a gravitational microlensing event. in t... | a massive reanalysis of microlensing events |
neutron stars are known to host extremely powerful magnetic fields. among other effects, one of the consequences of harboring such fields is the deformation of the neutron star structure, leading, together with rotation, to the emission of continuous gravitational waves (cgws). we present an extensive numerical study o... | modelling the deformability of magnetized neutron stars in the light of future continuous gravitational waves detection |
many hot jupiters (hjs) have been observed to have large obliquities or misalignments between the stellar spin axis and the orbital angular momentum of the planet. this observation hints that at least a portion of hjs formed through high-eccentricity migration, in which a cold jupiter is excited onto a highly eccentric... | forming hot jupiters via high-eccentricity migration: a preference for perpendicular planets |
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 pred... | confirming and characterizing new mean motion resonances in the kepler and tess catalogues |
fado comes from the latin word "fatum" that means fate or destiny. it is also a well known genre of portuguese music, and by choosing this acronym for this spectral synthesis tool we would like to pay tribute to portugal. the main goal of fado is to explore the star-formation and chemical enrichment history (the "fado"... | vizier online data catalog: fado code (gomes+, 2017) |
stellar population synthesis (sps) models are routinely used to interpret extragalactic observations at all redshifts. currently, the dominant source of uncertainty in sps modeling lies in the degeneracies associated with synthesizing and fitting complex stellar populations to observed galaxy spectra. to remedy this, w... | phat+manga: using resolved stellar populations to improve the recovery of star formation histories from galaxy spectra |
the tess mission has the potential to probe stellar rotation in millions of stars across the entire sky, but mission systematics—instrumental noise, observing gaps, and changes in detector sensitivity—have prevented recovery of rotation periods longer than 13.7 days. i used deep learning to see through tess systematics... | rotational characterization of tess stars with deep learning |
currently, we know of nearly one hundred compact binary mergers from the first three observation runs of ligo and virgo, and expect a "deluge" of new detections in the next few years. this wealth of new data provides us with crucial insights on the populations of binary compact objects, helping us to tackle some of the... | populations of binary compact-object mergers |
a robust numerical method for discrete two-sample ks-test calculation for is presented. the method is binning-independent and computationally efficient at large ratios of sample sizes. the method is used for binary stars population synthesis problem to test distributions of synthesized binary parameters against distrib... | numerical method for discrete two-sample ks-test in binary stars population synthesis problem |
binary_c-python provides a manager for and interface to the binary_c framework (ascl:2307.035), and rapidly evolves individual systems and populations of stars. it provides functions such as data processing tools and initial distribution functions for stellar properties. binary_c-python also includes tools to run large... | binary_c-python: stellar population synthesis tool and interface to binary_c |
we present our analysis of metal contributions from galaxies as observed in quasar absorption line spectra from 10 ≥ z ≥ 5.5 during the end of the epoch of reionization (eor). this was done with particle tracking done in-parallel in the latest technicolor dawn run and then linking absorbers to potential host galaxies i... | galaxy-absorber association in the epoch of reionization: galactic population luminosity distribution for different absorbers at 10 ≤ z ≤ 5.5 |
wind roche-lobe overflow (wrlof) is a mechanism of mass transfer in a binary system where the wind acceleration zone radius of the donor exceeds the roche-lobe radius and the stellar wind transfers mass to the accretor. the disagreement between the observed and modeled population of carbon-enhanced metal-poor (cemp) st... | applying wind roche-lobe overflow in binary evolution using mesa and posydon |
after 50 years, the moog spectrum synthesis code remains an essential and popular tool for the analysis of stellar spectra. this meeting-in-meeting will highlight some of the diverse applications and new directions of research enabled by moog, as well as impact this code has had on our understanding of stars and stella... | synthesizing the music of the stars |
we can learn a lot about the formation of compact objects, such as neutron stars and black holes, by studying the x-ray emission from accreting systems in nearby star-forming galaxies. the harder (e>10 kev) x-ray emission in particular allows strong discrimination among the accretion states and compact object types.... | young black hole and neutron star systems in the nearby star-forming galaxy m33: the nustar view |
modeling low mass stellar populations, like clusters and dwarf galaxies, with population synthesis models requires that we evaluate the role played by stochastic fluctuations in the sampling of the imf on the spectro-photometric properties of these sparse populations. interacting binaries may also modify the integrated... | modeling low mass stellar populations |
using an evolutionary population synthesis code, we modeled the universal, featureless x-ray luminosity function of high-mass x-ray binaries (hmxbs) in star-forming galaxies. we put constraints on the natal kicks, super-eddington accretion factor, as well as common envelope prescriptions usually adopted (i.e., the αce ... | high-mass x-ray binaries: evolutionary population synthesis modeling |
the synthesis of dust grains mostly takes place in the circumstellar envelopes (cses) of asymptotic giant branch (agb) stars. what are the precursor seeds of condensation nuclei and how do these particles evolve toward the micrometer sized grains that populate the interstellar medium? these are key questions of the nan... | abundance estimates in carbon star envelopes |
connecting star and planet properties in a single model is not straightforward. stellar population synthesis models are key to explore combined statistical constraints from stars and planets observations. the besançon stellar population synthesis model (robin et al. 2003, lagarde et al. 2017) includes now the stellar e... | chemical connections between low-mass stars and planets building blocks investigated by stellar population synthesis |
for decades, a subset of carbon-rich wr (wc) stars have been known to actively form dust despite their extreme environments. although these systems can produce copious amounts of dust, they have been commonly overlooked as significant sources of dust in the ism of galaxies in the local and early universe due to the per... | revisiting and resolving carbon-rich wolf-rayet dust factories |
binary systems are prevalent in both stellar clusters with high central densities and in the galactic field. i aim to understand the effects of dynamics by presenting a systematic comparison between the evolution and properties of identical initial binary populations placed in different environments. i explore a full r... | dynamics vs. isolated evolution: how do different environments affect binary populations? |
searching for distinctive signatures, which characterize different formation channels and environments of binary black holes (bbhs), is a crucial step towards the interpretation of current and future gravitational wave detections. in this talk, i will discuss the formation of merging bbhs in young star clusters (scs), ... | young star clusters: a nursery of merging binary black holes |
our understanding of galactic structure and evolution is far from complete. within the past twelve months we have learnt that the milky way is about 50% wider than was previously thought. as a consequence, new models are being developed that force us to reassess the kinematic structure of our galaxy. similarly, we need... | pn populations in the local group and distant stellar populations |
this negative image of ngc 5907 (originally published inmartinez-delgadoet al. 2008; click for the full view!) reveals the faint stellar stream that encircles the galaxy, forming loops around it a fossil of a recent merger. mergers between galaxies come in several different flavors: major mergers, in which the merging ... | featured image: a looping stellar stream |
stellar formation and evolution, as they apply to binary stars, reveal their underlying physical mechanisms through the properties of the observed binary star samples. by analyzing populations of binaries, we can study these processes in detail. in the era of large-scale time domain surveys, the acquisition of large sa... | synthesizing a sample of detached binary stars in the kepler field to probe the underlying stellar population |
we analyze the optical continuum of star-forming galaxies in the sloan digital sky survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. we fit models calculated with star formation and... | vizier online data catalog: mass, z, dust attenuation, and sfr relations (zahid+, 2017) |
in the last decade great strides have been made in understanding the role of binary stars in the evolution and shaping of planetary nebulæ (pne). observational efforts have mainly focused on finding close binaries with orbital periods of 1 day or less. those close binary systems make up around 1 in 5 pne, and constitut... | searching for long-period binary central stars of planetary nebulae with salt hrs |
the first glimpse of the spectral properties of z 7-10 galaxies has recently emerged. deep uv spectra have revealed intense emission from nebular ciii] and civ, implying a hard radiation field that is rarely seen at lower redshifts. unfortunately, we are currently unprepared to interpret these features, owing to shortc... | massive stellar populations at reionization-era metallicities with ultra-deep hst/cos spectroscopy |
we propose an ambitious adap to provide a statistically rigorous characterization of how the x-ray binary luminosity function (xlf) depends on host stellar population age and metallicity. we will make unique use of archival chandra, galex, swift, sdss, hubble, 2mass, spitzer, herschel, and a variety of other ancillary ... | a framework characterizing the metallicity and age dependent formation of x-ray binaries in galaxies near and far |
a neutron star emerging from the common-envelope phase may be paired with a helium-star companion. the helium star may eventually undergo a supernova explosion and form a double neutron-star system. compact-binary population-synthesis codes often treat the transition from the pre-supernova to the post-supernova state a... | double neutron-star formation from supernova natal kicks |
connecting star and planet properties in a single model is not straightforward. stellar population synthesis models are key to explore combined statistical constraints from stars and planets observations. the besançon stellar population synthesis model includes now the stellar evolutionary tracks computed with the stel... | chemical connections between low-mass stars and planets building blocks investigated by stellar population synthesis |
x-ray and extreme ultraviolet (xuv) radiation is likely shaping the observed population of short period exoplanets by powering blow-off of their atmospheres. the amount of atmosphere an individual planet might lose to xuv erosion depends on the history of its xuv irradiation, which could be 10-1000× higher when it form... | planets are shaped by their past: reconstructing the early xuv emission of exoplanet host stars |
the hubble deep and ultra deep fields are iconic, and almost certainly the most studied hst observations. wfirst will also have the opportunity to reach galaxies at the same extremely faint magnitudes, but with a fov 140 times that of hst wf3. this will open up the study of the highest redshift galaxies to the type of ... | simulating the first galaxies and quasars |
wickramasinghe et al. (2014) and briggs et al. (2015) have proposed that the strong magnetic fields observed in some single white dwarfs (mwds) are formed by an α—ω dynamo driven by differential rotation when two stars, the more massive one with a degenerate core, merge during common envelope (ce) evolution (ferrario e... | magnetic fields in interacting binaries |
the ligo/virgo detections of gravitational waves from merging black holes of ~= 30 solar mass suggest progenitor stars of low metallicity (z/z⊙ <~ 0.3). in this talk i will provide constrains on where the progenitors of gw150914 and gw170104 may have formed, based on advanced models of galaxy formation and evolution... | merging massive black holes the right place and the right time |
we present lte analysis of high resolution optical spectra for b-type hot pagb stars ls iv-04 1 and lb3116 (lse 237). the spectra of these high galactic latitude stars were obtained with the 3.9-m anglo-australian telescope (aat) and the ucles spectrograph. the standard 1d lte analysis with line-blanketed lte model atm... | high resolution optical spectroscopy of hot post-agb star candidates ls iv-04 1 and lb3116 |
this initial release provides a tool for a stellar population synthesis in our galaxy using the galactic model optimized for the bulge direction developed by koshimoto, baba, and bennett (2021), apj, 917, 78, and a forthcoming paper. the copyright of an included supplementary code, "option.c", belongs to ian a. bond an... | nkoshimoto/genstars: a tool for stellar population synthesis toward the galactic bulge |
rapster (rapid cluster evolution) models binary black hole population synthesis and the evolution of star clusters based on simple, yet realistic prescriptions. the code can generate large populations of dynamically formed binary black holes. rapster uses sevn (ascl:2206.019) to model the initial black hole mass spectr... | rapster: rapid population synthesis for binary black hole mergers in dynamical environments |
around 300,000 years after the big bang, the universe had cooled enough to combine and form neutral atoms. this signified the beginning of a time known as the dark ages. neutral matter began to fall into the dark matter gravitational wells that were seeded after the initial moments of the big bang. as the first stars a... | x-ray emission from early universe analog galaxies |
agn feedback is a critical regulator of galaxy growth. as well as curtailing star formation in diffuse, hot gas, it is increasingly understood to sometimes enhance star formation in the clumpy ism through shock-induced collapse of clouds. simulations have shown that such positive feedback may play a significant role in... | a local laboratory for studying positive feedback from supermassive black holes |
spectral synthesis enables the reconstruction of the star formation and chemical evolution histories (sfh & ceh) of a galaxy that are encoded in its spectral energy distribution (sed). most state-of-the-art population synthesis codes however consider only purely stellar emission and are hence inadequate for modelli... | quantifying the impact of agn and nebular emission on stellar population properties with rebetiko |
the formation efficiency of x-ray binaries (xrbs) is a key parameter for constraining their formation and evolution channels and for modeling the x-ray emission of galaxies at cosmological distances. we present results from our direct measurement of the formation efficiency of xrbs associated with young stellar populat... | the formation efficiency of x-ray binaries: insights from nearby galaxies |
we present an lte analysis of high resolution echelle optical spectra obtained with the 3.9-m anglo-australian telescope (aat) and the ucles spectrograph for a b1ib high galactic latitude supergiant hd119608. a fresh determination of the atmospheric parameters using line-blanketed lte model atmospheres and spectral syn... | high resolution optical spectroscopy of an intriguing high-latitude b-type star hd119608 |
far from the galactic suburbs where the sun resides, a cluster of stars in the nucleus of the milky way orbits a supermassive black hole. can chemical abundance measurements help us understand the formation history of the galactic center nuclear star cluster?studying stellar populationsmetallicity distributions for sta... | unusual metals in galactic center stars |
the kilo degree survey (kids) is one of the eso public surveys carried out with the vlt survey telescope (vst), equipped with the one square degree field of view and high angular resolution (0.2''/pixel) omegacam camera. kids is mainly designed for weak lensing studies, providing deep imaging in four optical bands (ugr... | rare treasures in the kids survey |
globular clusters has been proposed as testbeds for type ia supernovae (sne ia), which have high values in astrophysics, especially in cosmology and galactic chemical evolution. here, by using a detailed binary population synthesis (bps) approach, we studied the birthrates of sne ia from various of progenitor models in... | the birthrates of type ia supernovae in globular clusters |
we calculate the spectral energy distribution of the first galaxies which contain pre-main-sequence stars by using the stellar evolution code modules for experiments in stellar astrophysics, the spectra model bt-settl, and the stellar population synthesis code pegase. we calculate the galaxy spectral energy distributio... | first galaxy sed: contribution from pre-main-sequence stars |
each file contains the output of our population synthesis simulations (see table 1). the data files include both systems remaining bound and those that are disrupted. each system is logged at the time of the first sn and we store initial values of masses and period, the pre-cor-collapse and post-core collapse masses, p... | vizier online data catalog: massive runaway and walkaway stars models (renzo+, 2019) |
the chemical and kinematical properties of stars in the galactic halo provide a means to study the formation history of the milky way. stars formed within a satellite galaxy will bear the imprint of their host dark matter subhalo: star formation is less efficient in less massive protogalactic clumps, so we should obser... | contributions to the galactic halo from in-situ, kicked-out, and accreted stars |
we applied hydrodynamic modelling to the close-in sub-neptune corot-24b (m<5.7 mearth; r~3.7 rearth; 5-days orbit). because of its high temperature and low surface gravity, we obtained an unphysical mass-loss rate, three orders of magnitude higher than the maximum possible value given by the energy limited escape fo... | the "true" radius of hot sub-neptune planets and a theoretical way to estimate their minimum mass |
the majority of young massive stars are found in close binary systems. recently, dedicated observing campaigns have provided strong constraints on the binary fraction as well as the distribution of the parameters that characterize the binary systems: the masses of both components, the orbital period and eccentricities.... | massive binaries as progenitors for stellar explosions |
in most population synthesis calculations of close binary stars, the common envelope (ce) phase is modeled using a standard prescription based upon conservation of energy. in this prescription, the orbital separation of the secondary and giant core at the end of the ce phase is taken to be the orbital separation when t... | on the final orbital separation in common envelope evolution |
white dwarf-neutron star binaries are among the main progenitors for ultra-compact x-ray binaries. they spiral in to contact by emitting gravitational waves and depending on the mass of the white dwarf turn into stably transferring ultra-compact x-ray binaries or produce supernova-like events following a tidal disrupti... | white dwarf-neutron star binary progenitors for ultra-compact x-ray binaries |
we propose to find the optical counterparts for at least 40 high-mass x-ray binaries (hmxbs) in m33 using archival hst imaging data. we will align the data to the deep chandra x-ray catalog to search for optical counterpart candidates to the x-ray sources. the optical morphology and photometry of these counterparts wil... | finding and aging the population of high-mass x-ray binaries in m33 |
the ways in which galaxies acquire, process, enrich, and expel their gas---known as the "baryon cycle"---are among the most complex and important processes in astrophysics. hubble and its contemporaries have revealed much about the gas-galaxy connection at z<1. we anticipate rapid progress in observational studies o... | figuring out gas & galaxies in enzo (foggie): the gas-galaxy connection at z>2 |
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