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the nebular phase of lanthanide-rich ejecta of a neutron star merger (nsm) is studied by using a one-zone model, in which the atomic properties a represented by a single species, neodymium (nd). under the assumption that β-decay of r-process nuclei is the heat and ionization source, we solve the ionization and thermal ... | nebular emission from lanthanide-rich ejecta of neutron star merger |
isotope anomalies among planetary bodies provide key constraints on planetary genetics and the solar system's dynamical evolution. however, to unlock the full potential of these anomalies for constraining the processing, mixing, and transport of material in the disk it is essential to identify the main components respo... | elemental and isotopic variability in solar system materials by mixing and processing of primordial disk reservoirs |
we characterize magnetically driven accretion at radii between 1 and 100 au in protoplanetary discs, using a series of local non-ideal magnetohydrodynamic (mhd) simulations. the simulations assume a minimum mass solar nebula (mmsn) disc that is threaded by a net vertical magnetic field of specified strength. confirming... | magnetically driven accretion in protoplanetary discs |
the detection of ethanolamine (nh 2ch 2ch 2oh) in a molecular cloud in the interstellar medium confirms that a precursor of phospholipids is efficiently formed by interstellar chemistry. hence, ethanolamine could have been transferred from the proto-solar nebula to planetesimals and minor bodies of the solar system and... | discovery in space of ethanolamine, the simplest phospholipid head group |
h ii regions are ionized nebulae surrounding massive stars. they exhibit a wealth of emission lines that form the basis for estimation of chemical composition. heavy elements regulate the cooling of interstellar gas, and are essential to the understanding of several phenomena such as nucleosynthesis, star formation and... | temperature inhomogeneities cause the abundance discrepancy in h ii regions |
we propose an expression for a local planetesimal formation rate proportional to the instantaneous radial pebble flux. the result—a radial planetesimal distribution—can be used as an initial condition to study the formation of planetary embryos. we follow the idea that one needs particle traps to locally enhance the du... | planetesimal population synthesis: pebble flux-regulated planetesimal formation |
fast neutron-rich material ejected dynamically over ≲10 ms during the merger of a binary neutron star (bns) can give rise to distinctive electromagnetic counterparts to the system's gravitational-wave emission that serve as a "smoking gun" to distinguish between a bns and an ns-black hole merger. we present novel ab in... | grmhd simulations of neutron-star mergers with weak interactions: r-process nucleosynthesis and electromagnetic signatures of dynamical ejecta |
we present jwst near-infrared (nir) and mid-infrared (mir) spectroscopic observations of the nearby normal type ia supernova (sn) sn 2021aefx in the nebular phase at +255 days past maximum light. our near infrared spectrograph (nirspec) and mid infrared instrument observations, combined with ground-based optical data f... | a jwst near- and mid-infrared nebular spectrum of the type ia supernova 2021aefx |
we present a new method for inferring the metallicity (z) and ionization parameter (q) of h ii regions and star-forming galaxies using strong nebular emission lines (sels). we use bayesian inference to derive the joint and marginalized posterior probability density functions for z and q given a set of observed line flu... | izi: inferring the gas phase metallicity (z) and ionization parameter (q) of ionized nebulae using bayesian statistics |
young, rapidly spinning magnetars are invoked as central engines behind a diverse set of transient astrophysical phenomena, including gamma-ray bursts, superluminous supernovae (slsne), fast radio bursts (frbs), and binary neutron star (ns) mergers. however, a barrier to direct confirmation of the magnetar hypothesis i... | unveiling the engines of fast radio bursts, superluminous supernovae, and gamma-ray bursts |
we present a tutorial on the determination of the physical conditions and chemical abundances in gaseous nebulae. we also include a brief review of recent results on the study of gaseous nebulae, their relevance for the study of stellar evolution, galactic chemical evolution, and the evolution of the universe. one of t... | nebular spectroscopy: a guide on hii regions and planetary nebulae |
young solar-type stars are known to be strong x-ray emitters and their x-ray spectra have been widely studied. x-rays from the central star may play a crucial role in the thermodynamics and chemistry of the circumstellar material as well as in the atmospheric evolution of young planets. in this paper, we present model ... | the dispersal of protoplanetary discs - ii: photoevaporation models with observationally derived irradiating spectra |
the orion bar is the archetypal edge-on molecular cloud surface illuminated by strong ultraviolet radiation from nearby massive stars. our relative closeness to the orion nebula (about 1,350 light years away from earth) means that we can study the effects of stellar feedback on the parental cloud in detail. visible-lig... | compression and ablation of the photo-irradiated molecular cloud the orion bar |
massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. these processes have profound effects on the evolution of interstellar matter in our galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1-3 to the present day. the dom... | pdrs4all: a jwst early release science program on radiative feedback from massive stars |
we use a sample of 532 star-forming galaxies at redshifts z ≃ 1.4-2.6 with deep rest-frame optical spectra from the mosfire deep evolution field (mosdef) survey to place the first constraints on the nebular attenuation curve at high redshift. based on the first five low-order balmer emission lines detected in the compo... | the mosdef survey: the first direct measurements of the nebular dust attenuation curve at high redshift |
we measured gas-phase metallicity, ionisation parameter, and dust extinction for a representative sample of 1795 local star-forming galaxies using integral field spectroscopy from the sdss-iv manga survey. we self-consistently derive these quantities by comparing observed line fluxes with photoionisation models using a... | sdss iv manga: metallicity and ionisation parameter in local star-forming galaxies from bayesian fitting to photoionisation models |
context. the spatial distribution of elemental abundances in the disc of our galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. gradients can be traced using several types of objects as, for instance, (young and old) stars, open clust... | the gaia-eso survey: radial distribution of abundances in the galactic disc from open clusters and young-field stars |
we report the serendipitous discovery of an [o iii] λ λ4959/5007 and hα line emitter in the epoch of reionization (eor) with the james webb space telescope (jwst) commissioning data taken in the nircam wide-field slitless spectroscopy (wfss) mode. located ~55″ away from the flux calibrator p330-e, this galaxy exhibits ... | first peek with jwst/nircam wide-field slitless spectroscopy: serendipitous discovery of a strong [o iii]/hα emitter at z = 6.11 |
with its exquisite sensitivity, wavelength coverage, and spatial and spectral resolution, the james webb space telescope (jwst) is poised to revolutionize our view of the distant, high-redshift (z > 5) universe. while webb's spectroscopic observations will be transformative for the field, photometric observations pl... | first light and reionisation epoch simulations (flares) - vi. the colour evolution of galaxies z = 5-15 |
ultraviolet (uv) observations of local star-forming galaxies have begun to establish an empirical baseline for interpreting the rest-uv spectra of reionization-era galaxies. however, existing high-ionization emission line measurements at z > 6 (w_{c riptsciv,0}{} ≳ 20 å) are uniformly stronger than observed locally ... | extremely metal-poor galaxies with hst/cos: laboratories for models of low-metallicity massive stars and high-redshift galaxies |
roche lobe overflow from a donor star onto a black hole or neutron star binary companion can evolve to a phase of unstable runaway mass transfer, lasting as short as hundreds of orbits (≲102 yr for a giant donor) and eventually culminating in a common-envelope event. the highly super-eddington accretion rates achieved ... | radio nebulae from hyperaccreting x-ray binaries as common-envelope precursors and persistent counterparts of fast radio bursts |
in recent years, sea spray as well as the biological material it contains has received increased attention as a source of ice-nucleating particles (inps). such inps may play a role in remote marine regions, where other sources of inps are scarce or absent. in the arctic, these inps can influence water-ice partitioning ... | the ice-nucleating activity of arctic sea surface microlayer samples and marine algal cultures |
this is the second paper in a series aimed at investigating the main sources of uncertainty in measuring the observable parameters in galaxies from their spectral energy distributions (seds). in the first paper we presented a detailed account of the photometric redshift measurements and an error analysis of this proces... | a critical assessment of stellar mass measurement methods |
we investigate line formation processes in type iib supernovae (sne) from 100 to 500 days post-explosion using spectral synthesis calculations. the modelling identifies the nuclear burning layers and physical mechanisms that produce the major emission lines, and the diagnostic potential of these. we compare the model c... | late-time spectral line formation in type iib supernovae, with application to sn 1993j, sn 2008ax, and sn 2011dh |
we use non-local thermal equilibrium radiative transport modeling to examine observational signatures of sub-chandrasekhar mass double detonation explosions in the nebular phase. results range from spectra that look like typical and subluminous type ia supernovae (sne) for higher mass progenitors to spectra that look l... | nebular models of sub-chandrasekhar mass type ia supernovae: clues to the origin of ca-rich transients |
the explosion of a supernova releases almost instantaneously about 10^{51} ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. the stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a s... | radio emission from supernova remnants |
we use deep spectroscopy from the hubble space telescope wide-field-camera 3 ir grisms combined with broadband photometry to study the stellar populations, gas ionization and chemical abundances in star-forming galaxies at z ~ 1.1-2.3. the data stem from the candels lyα emission at reionization (clear) survey. at these... | clear: the ionization and chemical-enrichment properties of galaxies at 1.1 < z < 2.3 |
we report new polarimetric and photometric maps of the massive star-forming region omc-1 using the hawc+ instrument on the stratospheric observatory for infrared astronomy. we present continuum polarimetric and photometric measurements of this region at 53, 89, 154, and 214 μm at angular resolutions of 5″, 8″, 14″, and... | hawc+/sofia multiwavelength polarimetric observations of omc-1 |
measurement of the mass of particles in the mega- to gigadalton range is challenging with conventional mass spectrometry. although this mass range appears optimal for nanomechanical resonators, nanomechanical mass spectrometers often suffer from prohibitive sample loss, extended analysis time, or inadequate resolution.... | neutral mass spectrometry of virus capsids above 100 megadaltons with nanomechanical resonators |
recent observations have revealed that the remnants of stellar-coalescence transients are bipolar. this raises the questions of how these bipolar morphologies arise and what they teach us about the mechanisms of mass ejection during stellar mergers and common-envelope phases. in this paper, we analyze hydrodynamic simu... | bound outflows, unbound ejecta, and the shaping of bipolar remnants during stellar coalescence |
we present a search for helium in the upper atmospheres of three sub-neptune-sized planets to investigate the origins of these ubiquitous objects. the detection of helium for a low-density planet would be strong evidence for the presence of a primary atmosphere accreted from the protoplanetary nebula because large amou... | nondetection of helium in the upper atmospheres of three sub-neptune exoplanets |
we present results on the star formation rate (sfr) versus stellar mass (m*) relation (i.e., the “main sequence”) among star-forming galaxies at 1.37 ≤ z ≤ 2.61 using the mosfire deep evolution field (mosdef) survey. based on a sample of 261 galaxies with hα and hβ spectroscopy, we have estimated robust dust-corrected ... | the mosdef survey: dissecting the star formation rate versus stellar mass relation using hα and hβ emission lines at z ∼ 2 |
the progenitor systems and explosion mechanism of type ia supernovae are still unknown. currently favoured progenitors include double-degenerate systems consisting of two carbon-oxygen white dwarfs with thin helium shells. in the double-detonation scenario, violent accretion leads to a helium detonation on the more mas... | on the fate of the secondary white dwarf in double-degenerate double-detonation type ia supernovae |
accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. in particular, black-hole transients have outflows whose properties are strongly coupled to those of the accretion flow. this includes x-ray winds of ionized material, expelled from the accretion disk en... | regulation of black-hole accretion by a disk wind during a violent outburst of v404 cygni |
constraints on the composition of mars principally derive from chemical analyses of a set of martian meteorites that rely either on determinations of their refractory element abundances or isotopic compositions. both approaches, however, lead to models of mars that are unable to self-consistently explain major element ... | geophysical and cosmochemical evidence for a volatile-rich mars |
asymmetric shapes and evidence for binary central stars suggest a common-envelope origin for many bipolar planetary nebulae. the bipolar components of the nebulae are observed to expand faster than the rest, and the more slowly expanding material has been associated with the bulk of the envelope ejected during the comm... | bipolar planetary nebulae from common-envelope evolution of binary stars |
the abundance of refractory elements in giant planets can provide key insights into their formation histories1. owing to the low temperatures of the solar system giants, refractory elements condense below the cloud deck, limiting sensing capabilities to only highly volatile elements2. recently, ultra-hot giant exoplane... | vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet |
using a large sample of spectroscopically confirmed z∼ 3 galaxies, we establish an empirical relationship between reddening (e(b-v)), neutral gas covering fraction ({f}{{cov}}({{h}} {{i}})), and the escape of ionizing (lyman continuum, lyc) photons. our sample includes 933 galaxies at z∼ 3,121 of which have deep spectr... | the connection between reddening, gas covering fraction, and the escape of ionizing radiation at high redshift |
we present powderday (available at https://github.com/dnarayanan/powderday), a flexible, fast, open-source dust radiative transfer package designed to interface with both idealized and cosmological galaxy formation simulations. powderday builds on fsps stellar population synthesis models, and hyperion dust radiative tr... | powderday: dust radiative transfer for galaxy simulations |
eruptive mass loss of massive stars prior to supernova (sn) explosion is key to understanding their evolution and end fate. an observational signature of pre-sn mass loss is the detection of an early, short-lived peak prior to the radioactive-powered peak in the lightcurve of the sn. this is usually attributed to the s... | probing pre-supernova mass loss in double-peaked type ibc supernovae from the zwicky transient facility |
current trends to pre-train capable large language models (llms) mostly focus on scaling of model and dataset size. however, the quality of pre-training data is an important factor for training powerful llms, yet it is a nebulous concept that has not been fully characterized. therefore, we use the recently proposed tas... | beyond scale: the diversity coefficient as a data quality metric demonstrates llms are pre-trained on formally diverse data |
the chemical enrichment of the universe; the mass spectrum of planetary nebulae, white dwarfs and gravitational wave progenitors; the frequency distribution of type i and ii supernovae; the fate of exoplanets ... a multitude of phenomena which is highly regulated by the amounts of mass that stars expel through a powerf... | evolution and mass loss of cool ageing stars: a daedalean story |
the aggregation of inorganic particles with high mass ratio will form a heterogeneous electric field in the solid polymer electrolytes (spes), which is difficult to be compatible with lithium anode, leading to inadequate ionic conductivity. herein, a facile spray drying method is adopted to increase the mass ratio of i... | a homogenous solid polymer electrolyte prepared by facile spray drying method is used for room-temperature solid lithium metal batteries |
the fornax cluster provides a uniquely compact laboratory in which to study the detailed history of early-type galaxies and the role played by the environment in driving their evolution and their transformation from late-type galaxies. using the superb capabilities of the multi unit spectroscopic explorer on the very l... | fornax3d project: overall goals, galaxy sample, muse data analysis, and initial results |
we present keck/mosfire spectra of the diagnostic nebular emission lines [o iii]λ λ 5007,4959, [o ii]λ 3727, and hβ for a sample of 15 redshift z≃ 3.1{--}3.7 lyα emitters (laes) and lyman break galaxies (lbgs). in conjunction with spectra from other surveys, we confirm earlier indications that laes have a much higher [... | a hard ionizing spectrum in z = 3-4 lyα emitters with intense [o iii] emission: analogs of galaxies in the reionization era? |
using high-resolution data from the galactic arecibo l-band feed array hi (galfa-hi) survey, we show that linear structure in galactic neutral hydrogen (hi) correlates with the magnetic field orientation implied by planck 353 ghz polarized dust emission. the structure of the neutral interstellar medium is more tightly ... | neutral hydrogen structures trace dust polarization angle: implications for cosmic microwave background foregrounds |
we present high-cadence optical and ultraviolet light curves of the normal type ia supernova (sn) 2021aefx, which shows an early bump during the first two days of observation. this bump may be a signature of interaction between the exploding white dwarf and a nondegenerate binary companion, or it may be intrinsic to th... | constraining the progenitor system of the type ia supernova 2021aefx |
in many applications where small, similar-sized droplets are needed, ultrasonic nebulizers are employed. little is known about the mechanism of nebulization, for example about what determines the median droplet size. even less understood, is the droplet size distribution, which is often simply fitted with a log-normal ... | size distributions of droplets produced by ultrasonic nebulizers |
recent analyses have shown that the concluding stages of giant planet formation are accompanied by the development of a large-scale meridional flow of gas inside the planetary hill sphere. this circulation feeds a circumplanetary disk that viscously expels gaseous material back into the parent nebula, maintaining the s... | formation of giant planet satellites |
chondrules are the millimetre-scale, previously molten, spherules found in most meteorites. before chondrules formed, large differentiating planetesimals had already accreted. volatile-rich olivine reveals that chondrules formed in extremely solid-rich environments, more like impact plumes than the solar nebula. the un... | impact jetting as the origin of chondrules |
a noise-based non-parametric technique for detecting nebulous objects, for example, irregular or clumpy galaxies, and their structure in noise is introduced. “noise-based” and “non-parametric” imply that this technique imposes negligible constraints on the properties of the targets and that it employs no regression ana... | noise-based detection and segmentation of nebulous objects |
deep observations are revealing a growing number of young galaxies in the first billion years of cosmic time1. compared to typical galaxies at later times, they show more extreme emission-line properties2, higher star formation rates3, lower masses4, and smaller sizes5. however, their faintness precludes studies of the... | analogues of primeval galaxies two billion years after the big bang |
we present alma observations of co isotopes and 1.3 mm continuum emission toward the n159e-papillon nebula in the large magellanic cloud (lmc). the spatial resolution is 0.″25-0.″28 (0.06-0.07 pc), which is a factor of 3 higher than previous alma observations in this region. the high resolution allowed us to resolve hi... | an alma view of molecular filaments in the large magellanic cloud. i. the formation of high-mass stars and pillars in the n159e-papillon nebula triggered by a cloud-cloud collision |
we use medium-resolution jwst/nirspec observations from the cosmic evolution early release science survey to place the first constraints on dust attenuation and star formation based on paschen lines for a sizable sample of 63 galaxies at redshifts z = 1.0-3.1. our analysis indicates strong correlations between the balm... | paschen-line constraints on dust attenuation and star formation at z 1-3 with jwst/nirspec |
selecting the first galaxies at z > 7 - 10 from jwst surveys is complicated by z < 6 contaminants with degenerate photometry. for example, strong optical nebular emission lines at z < 6 may mimic jwst/nircam photometry of z > 7-10 lyman-break galaxies (lbgs). dust-obscured 3 < z < 6 galaxies in partic... | broad emission lines in optical spectra of hot, dust-obscured galaxies can contribute significantly to jwst/nircam photometry |
we place statistical constraints on type ia supernova (sn ia) progenitors using 227 nebular-phase spectra of 111 sne ia. we find no evidence of stripped companion emission in any of the nebular-phase spectra. upper limits are placed on the amount of mass that could go undetected in each spectrum using recent hydrodynam... | nebular spectra of 111 type ia supernovae disfavour single-degenerate progenitors |
binary neutron star mergers are thought to be one of the dominant sites of production for rapid neutron capture elements, including platinum and gold. since the discovery of the binary neutron star merger gw170817, and its associated kilonova at2017gfo, numerous works have attempted to determine the composition of its ... | constraints on the presence of platinum and gold in the spectra of the kilonova at2017gfo |
in the last few years, prominent high-ionization nebular emission lines (i.e., o iii], c iii], c iv, and he ii) have been observed in the deep uv spectra of z ∼ 5-7 galaxies, indicating that extreme radiation fields characterize reionization-era systems. these lines have been linked to the leakage of lyman continuum ph... | intense c iv and he ii emission in z ∼ 0 galaxies: probing high-energy ionizing photons |
we have simulated a common envelope interaction between a 0.88 m⊙, 90 r⊙, red giant branch star, and a 0.6 m⊙, compact companion with the smoothed particle hydrodynamics code, phantom, from the beginning of the roche lobe overflow phase to the beginning of the self-regulated inspiral, at three different resolutions. th... | extending common envelope simulations from roche lobe overflow to the nebular phase |
the physical properties of epoch of reionization (eor) galaxies are still poorly constrained by observations. to better understand the ionizing properties of galaxies in the eor, we investigate deep, rest-frame ultraviolet (uv) spectra of ≃500 star-forming galaxies at 3 ≤ z ≤ 5 selected from the public eso-vandels spec... | the vandels survey: the ionizing properties of star-forming galaxies at 3 ≤ z ≤ 5 using deep rest-frame ultraviolet spectroscopy |
we utilize theoretical models of population iii stellar + nebular spectra to investigate the prospects of observing and accurately identifying population iii galaxies with jwst using both deep imaging and spectroscopy. we investigate a series of different colour cuts, finding that a combination of nircam and miri photo... | on the observability and identification of population iii galaxies with jwst |
the majority of discovered exoplanetary systems harbour a new class of planets, bodies that are typically several times more massive than the earth but that orbit their host stars well inside the orbit of mercury. the origin of these close-in super-earths and mini-neptunes is one of the major unanswered questions in pl... | the formation of super-earths and mini-neptunes with giant impacts |
stellar population synthesis techniques for predicting the observable light emitted by a stellar population have extensive applications in numerous areas of astronomy. however, accurate predictions for small populations of young stars, such as those found in individual star clusters, star-forming dwarf galaxies, and sm... | slug - stochastically lighting up galaxies - iii. a suite of tools for simulated photometry, spectroscopy, and bayesian inference with stochastic stellar populations |
deep spectroscopy of galaxies in the reionization era has revealed intense c iii] and c iv line emission (equivalent width, ew >15-20 å). in order to interpret the nebular emission emerging at z > 6, we have begun targeting rest-frame ultraviolet (uv) emission lines in galaxies with large specific star formation ... | rest-frame uv spectroscopy of extreme [o iii] emitters at 1.3 < z < 3.7: toward a high-redshift uv reference sample for jwst |
renazzo-type carbonaceous (cr) chondrites are distinct from most other chondrites in having younger chondrule 26al-26mg ages, but the significance of these ages and whether they reflect true formation times or spatial variations of the 26al/27al ratio within the solar protoplanetary disk are a matter of debate. to addr... | hf-w chronology of cr chondrites: implications for the timescales of chondrule formation and the distribution of 26al in the solar nebula |
the detailed velocity structure of the diffuse x-ray emitting intra-cluster medium (icm) remains one of the last missing key ingredients in understanding the microphysical properties of these hot baryons and constraining our models of the growth and evolution of structure on the largest scales in the universe. direct m... | constraining gas motions in the intra-cluster medium |
we derive hα fluxes for a large spectroscopic and photometric-redshift-selected sample of sources over goods-north and south in the redshift range z = 3.8-5.0 with deep hubble space telescope (hst), spitzer/irac, and ground-based observations. the hα flux is inferred based on the offset between the irac 3.6 μm flux and... | inferred h⍺ flux as a star formation rate indicator at z ~ 4-5: implications for dust properties, burstiness, and the z = 4-8 star formation rate functions |
the 30 doradus (30 dor) nebula in the large magellanic cloud (lmc) is the brightest hii region in the local group and a prototype starburst similar to those found in high redshift galaxies. it is thus a stepping stone to understand the complex formation processes of stars in starburst regions across the universe. here,... | the vlt-flames tarantula survey. xxix. massive star formation in the local 30 doradus starburst |
we present observations of sn 2020fqv, a virgo-cluster type ii core-collapse supernova (ccsn) with a high temporal resolution light curve from the transiting exoplanet survey satellite (tess) covering the time of explosion; ultraviolet (uv) spectroscopy from the hubble space telescope (hst) starting 3.3 d post-explosio... | progenitor and close-in circumstellar medium of type ii supernova 2020fqv from high-cadence photometry and ultra-rapid uv spectroscopy |
the radioactively powered transient following a binary neutron star merger, known as a kilonova (kn), is expected to enter the steady-state nebular phase a few days after merger. steady-state holds until thermal reprocessing time-scales become long, at which point the temperature and ionization states need to be evolve... | on the validity of steady-state for nebular phase kilonovae |
distant luminous lyman-α emitters (laes) are excellent targets for spectroscopic observations of galaxies in the epoch of reionisation (eor). we present deep high-resolution (r = 5000) vlt/x-shooter observations, along with an extensive collection of photometric data of cola1, a proposed double peaked lae at z = 6.6. w... | confirmation of double peaked lyα emission at z = 6.593. witnessing a galaxy directly contributing to the reionisation of the universe |
ngc 1052-df2, an ultra-diffuse galaxy (udg), has been the subject of intense debate. its alleged absence of dark matter, and the brightness and number excess of its globular clusters (gcs) at an initially assumed distance of 20 mpc suggest a new formation channel for udgs. we present the first systematic spectroscopic ... | the ultra-diffuse galaxy ngc 1052-df2 with muse. ii. the population of df2: stars, clusters, and planetary nebulae |
as deep spectroscopic campaigns extend to higher redshifts and lower stellar masses, the interpretation of galaxy spectra depends increasingly upon models for very young stellar populations. here we present new hst/cos ultraviolet spectroscopy of seven nearby (<120 mpc) star-forming regions hosting very young stella... | ultraviolet spectra of extreme nearby star-forming regions: evidence for an overabundance of very massive stars |
winds from young massive stars contribute a large amount of energy to their host molecular clouds. this has consequences for the dynamics and observable structure of star-forming clouds. in this paper, we present radiative magnetohydrodynamic simulations of turbulent molecular clouds that form individual stars of 30, 6... | the geometry and dynamical role of stellar wind bubbles in photoionized h ii regions |
the streaming instability is a popular candidate for planetesimal formation by concentrating dust particles to trigger gravitational collapse. however, its robustness against the physical conditions expected in protoplanetary disks is unclear. in particular, particle stirring by turbulence may impede the instability. t... | how efficient is the streaming instability in viscous protoplanetary disks? |
despite significant progress both observationally and theoretically, the origin of high-ionization nebular he ii emission in galaxies dominated by stellar photoionization remains unclear. accretion-powered radiation from high-mass x-ray binaries (hmxbs) is still one of the leading proposed explanations for the missing ... | high-mass x-ray binaries in nearby metal-poor galaxies: on the contribution to nebular he ii emission |
data suggest that most rocky exoplanets with orbital period p < 100 days ("hot" rocky exoplanets) formed as gas-rich sub-neptunes that subsequently lost most of their envelopes, but whether these rocky exoplanets still have atmospheres is unknown. we identify a pathway by which 1-1.7 r⊕ (1-10 m⊕) rocky exoplanets wi... | water on hot rocky exoplanets |
we investigate the relation between the optical extinction (av) and the hydrogen column density (nh) determined from x-ray observations of a large sample of galactic sightlines towards 35 supernova remnants, 6 planetary nebulae and 70 x-ray binaries for which nh was determined in the literature with solar abundances. w... | the gas-to-extinction ratio and the gas distribution in the galaxy |
galaxies occupy different regions of the [o iii]λ5007/h β-versus-[n ii]λ6584/h α emission-line ratio diagram in the distant and local universe. we investigate the origin of this intriguing result by modelling self-consistently, for the first time, nebular emission from young stars, accreting black holes (bhs) and older... | synthetic nebular emission from massive galaxies - i: origin of the cosmic evolution of optical emission-line ratios |
we hypothesize that differences in the temperatures at which the rocky material condensed out of the nebula gas can lead to differences in the composition of key rocky species (e.g. fe, mg, si, ca, al, na) and thus planet bulk density. such differences in the observed bulk density of planets may occur as a function of ... | a new class of super-earths formed from high-temperature condensates: hd219134 b, 55 cnc e, wasp-47 e |
it has recently been noted that there seems to be a strong correlation between planetary nebulae with close binary central stars and highly enhanced recombination line abundances. we present new deep spectra of seven objects known to have close binary central stars, and find that the heavy element abundances derived fr... | confirmation of the link between central star binarity and extreme abundance discrepancy factors in planetary nebulae |
superluminous supernovae (slsne) of type ic have a tendency to occur in faint host galaxies which are likely to have low mass and low metallicity. ptf12dam is one of the closest and best-studied superluminous explosions that has a broad and slowly fading light curve similar to sn 2007bi. here we present new photometry ... | the host galaxy and late-time evolution of the superluminous supernova ptf12dam |
we analyze the x-ray spectra of the ~8000 sources detected in the cygnus ob2 chandra legacy survey (this focus issue), with the goals of characterizing the coronal plasma of the young low-mass stars in the region and estimating their intrinsic x-ray luminosities. we adopt two different strategies for x-ray sources for ... | x-ray spectral characterization of the young cygnus ob2 population |
we have studied porphyritic olivine-rich chondrules of the carbonaceous chondrite kaba (cv3) by combined high-resolution x-ray mapping, quantitative electron microprobe analyses, and oxygen isotopic analyses via secondary ion mass spectrometry. these chondrules contain smaller inner-chondrule olivine grains characteriz... | formation of cv chondrules by recycling of amoeboid olivine aggregate-like precursors |
we present constraints on the massive star and ionized gas properties for a sample of 62 star-forming galaxies at z ~ 2.3. using bpass stellar population models, we fit the rest-uv spectra of galaxies in our sample to estimate age and stellar metallicity which, in turn, determine the ionizing spectrum. in addition to t... | the mosdef-lris survey: the connection between massive stars and ionized gas in individual galaxies at z ∼ 2 |
ionized nebulae are key to understanding the chemical composition and evolution of the universe. among these nebulae, h~{\sc ii} regions and planetary nebulae are particularly important as they provide insights into the present and past chemical composition of the interstellar medium, along with the nucleosynthetic pro... | the abundance discrepancy in ionized nebulae: which are the correct abundances? |
context. the region around the h2o ice line, due to its higher surface density, seems to be the ideal location to form planets. the core of jupiter, as well as the cores of close-in gas giants are therefore thought to form in this region of the disk. nevertheless, constraining the formation location of individual plane... | jupiter formed as a pebble pile around the n2 ice line |
we present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova (slsn) sn 2015bn, at redshift z = 0.1136, spanning +250-400 days after maximum light. the light curve exhibits a steepening in the decline rate from 1.4 mag (100 days)-1 to 1.7 mag (100 days)-1, suggestive of a significant d... | superluminous supernova sn 2015bn in the nebular phase: evidence for the engine-powered explosion of a stripped massive star |
convergent disk migration has long been suspected to be responsible for forming planetary systems with a chain of mean-motion resonances (mmrs). dynamical evolution over time could disrupt the delicate resonant configuration. we present toi-1136, a 700 ± 150 myr old g star hosting at least six transiting planets betwee... | toi-1136 is a young, coplanar, aligned planetary system in a pristine resonant chain |
the nature of fast radio bursts (frb) has been extensively debated. here we investigate frb121102, detected at arecibo telescope and remarkable for its unusually large spectral index. after extensive study we conclude that the spectral index is caused by a nebula with free-free absorption. we find that putative nebula ... | the arecibo fast radio burst: dense circum-burst medium |
we present a new basis for scaling abundances with total metallicity in nebular photoionization models, based on extensive milky way stellar abundance data, to replace the uniform scaling normally used in the analysis of h ii regions. our goal is to provide a single scaling method and local abundance reference standard... | abundance scaling in stars, nebulae and galaxies |
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... | stellar absorption line analysis of local star-forming galaxies: the relation between stellar mass, metallicity, dust attenuation, and star formation rate |
fast radio bursts (frbs) are observed to be highly polarized. most have high linear polarization but a small fraction shows significant circular polarization. we systematically investigate a variety of polarization mechanisms of frbs within the magnetar theoretical framework considering two emission sites inside and ou... | polarization of fast radio bursts: radiation mechanisms and propagation effects |
sbs 0335 - 052e, one of the most metal-poor (z ∼ 3-4{{ per cent}} z⊙) he ii-emitter starbursts known in the nearby universe, is studied using optical vlt/muse spectroscopic and chandra x-ray observations. we spatially resolved the spectral map of the nebular he ii λ4686 emission from which we derived for the first time... | the extended he ii λ4686 emission in the extremely metal-poor galaxy sbs 0335 - 052e seen with muse |
we present muse deep integral-field unit spectroscopy of three planetary nebulae (pne) with high-abundance discrepancy factors (adf > 20): ngc 6778, m 1-42, and hf 2-2. we have constructed flux maps for more than 40 emission lines, and use them to build extinction, electron temperature (te), electron density (ne), a... | muse spectroscopy of planetary nebulae with high abundance discrepancies |
metal-poor nearby galaxies hosting massive stars have a fundamental role to play in our understanding of both high-redshift galaxies and low-metallicity stellar populations. but while much attention has been focused on their bright nebular gas emission, the massive stars that power it remain challenging to constrain. h... | direct constraints on the extremely metal-poor massive stars underlying nebular c iv emission from ultra-deep hst/cos ultraviolet spectroscopy |
finding reliable indicators of lyman continuum (ly c) photon leakage from galaxies is essential in order to infer their escape fraction in the epoch of reionization, where direct measurements of ly c flux are impossible. to this end, here we investigate whether strong c iv λλ1548, 1550 emission in the rest-frame uv spe... | strong c iv emission from star-forming galaxies: a case for high lyman continuum photon escape |
fullerenes have recently been detected in various circumstellar and interstellar environments, raising the question of their formation pathway. it has been proposed that they can form at the low densities found in the interstellar medium by the photo-chemical processing of large polycyclic aromatic hydrocarbons (pahs).... | top-down formation of fullerenes in the interstellar medium |
understanding high-mass star formation is one of the top-priority issues in astrophysics. recent observational studies have revealed that cloud-cloud collisions may play a role in high-mass star formation in several places in the milky way and the large magellanic cloud. the trifid nebula m20 is a well-known galactic h... | triggered o star formation in m20 via cloud-cloud collision: comparisons between high-resolution co observations and simulations |
context. for up to a few millions of years, pebbles must provide a quasi-steady inflow of solids from the outer parts of protoplanetary disks to their inner regions.aims: we wish to understand how a significant fraction of the pebbles grows into planetesimals instead of being lost to the host star.methods: we examined ... | formation of dust-rich planetesimals from sublimated pebbles inside of the snow line |
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