adsabs/SciX_UAT_keywords huggingface dataset:
Sputtering of Presolar Grains via Galactic Cosmic Rays in the Interstellar Medium

The sputtering rate of presolar silicon carbide grains due to galactic cosmic rays has been computed for their experimentally deduced lifetimes (∼1 Gyr) in the interstellar medium. An ion target simulator, SDTrimSP, was used to model the sputtering of interstellar grains with varying sizes and thicknesses of the ice mantle formed around the grain during their journey through the interstellar medium. Temperature, composition, and density for four different types of molecular cloud environments (quiescent, low-mass young stellar objects (YSOs), intermediate-mass YSOs, and high-mass YSO weak processing) considered indicate the sputtering rate on the mantle ice composition depends on water composition to a certain extent. The model simulations indicate galactic cosmic ray(s) with an energy range from 10 MeV to 1 GeV are just capable of sputtering/destructing ∼13%-15% of the grain itself. This value, stretched over 1 Gyr is not as significant as the other destruction processes and therefore can be classified as a minor destruction process. The effect of galactic cosmic rays on the ice mantle and core is also noted with particular emphasis on amorphization/recoils generated inside the SiC core and their distribution within the grain.

Keywords: galactic cosmic rays; interstellar medium; carbonaceous grains
The First Habitable-zone Earth-sized Planet from TESS. III. Climate States and Characterization Prospects for TOI-700 d

We present self-consistent three-dimensional climate simulations of possible habitable states for the newly discovered habitable-zone Earth-sized planet TOI-700 d. We explore a variety of atmospheric compositions, pressures, and rotation states for both ocean-covered and completely desiccated planets in order to assess the planet's potential for habitability. For all 20 of our simulated cases, we use our climate model outputs to synthesize transmission spectra, combined-light spectra, and integrated broadband phase curves. These climatologically informed observables will help the community assess the technological capabilities necessary for future characterization of this planet—as well as similar transiting planets discovered in the future—and will provide a guide for distinguishing possible climate states if one day we do obtain sensitive spectral observations of a habitable planet around an M star. We find that TOI-700 d is a strong candidate for a habitable world and can potentially maintain temperate surface conditions under a wide variety of atmospheric compositions. Unfortunately, the spectral feature depths from the resulting transmission spectra and the peak flux and variations from our synthesized phase curves for TOI-700 d do not exceed 10 ppm. This will likely prohibit the James Webb Space Telescope from characterizing its atmosphere; however, this motivates the community to invest in future instrumentation that perhaps can one day reveal the true nature of TOI-700 d and to continue to search for similar planets around less distant stars.

Keywords: exoplanet atmospheres; habitable planets; low mass stars; astronomical models; transit photometry; exoplanet detection methods; direct imaging
What Are the Radial Distributions of Density, Outflow Rates, and Cloud Structures in the M82 Wind?

Galactic winds play essential roles in the evolution of galaxies through the feedback they provide. Despite intensive studies of winds, the radial distributions of their properties and feedback are rarely observable. Here we present such measurements for the prototypical starburst galaxy, M82, based on observations by the Subaru Telescope. We determine the radial distribution of outflow densities (n e ) from the spatially resolved [S II] λλ6717, 6731 emission lines. We find that n e drops from 200 to 40 cm-3 with radius (r) between 0.5 and 2.2 kpc with a best-fit power-law index of r -1.2. Combined with resolved Hα lines, we derive mass, momentum, and energy outflow rates, which drop quite slowly (almost unchanged within error bars) over this range of r. This suggests that the galactic wind in M82 can carry mass, momentum, and energy from the central regions to a few kiloparsecs with minimal losses. We further derive outflow cloud properties, including size and column densities. The clouds we measure have pressures and densities that are too high to match those from recent theoretical models and numerical simulations of winds. By comparing with a sample of outflows in local star-forming galaxies studied with UV absorption lines, the above-derived properties for M82 outflows match well with the published scaling relationships. These matches suggest that the ionized gas clouds traced in emission and absorption are strongly related. Our measurements motivate future spatially resolved studies of galactic winds, which is the only way to map the structure of their feedback effects.

Keywords: galaxy evolution; galactic winds; galaxy kinematics; starburst galaxies
Constraints on Planetesimal Accretion Inferred from Particle-size Distribution in CO Chondrites

The formation of planetesimals was a key step in the assemblage of planetary bodies, yet many aspects of their formation remain poorly constrained. Notably, the mechanism by which chondrules-submillimetric spheroids that dominate primitive meteorites-were incorporated into planetesimals remains poorly understood. Here we classify and analyze particle-size distributions in various CO carbonaceous chondrites found in the Atacama Desert. Our results show that the average circle-equivalent diameters of chondrules define a positive trend with the petrographic grade, which reflects the progressive role of thermal metamorphism within the CO parent body. We show that this relationship could not have been established by thermal metamorphism alone but rather by aerodynamic sorting during accretion. By modeling the self-gravitational contraction of clumps of chondrules, we show that (i) the accretion of the CO parent body(ies) would have generated a gradual change of chondrule size with depth in the parent body, with larger chondrules being more centrally concentrated than smaller ones, and (ii) any subsequent growth by pebble accretion would have been insignificant. These findings give substantial support to the view that planetesimals formed via gravitational collapse.

Keywords: asteroids; chondrites; accretion; protoplanetary disks; planetesimals
A Measurement of the Hubble Constant Using Gravitational Waves from the Binary Merger GW190814

We present a test of the statistical method introduced by Bernard F. Shutz in 1986 using only gravitational waves to infer the Hubble constant (H0) from GW190814, the first high-probability neutron-star-black hole (NS-BH) merger candidate detected by the Laser Interferometer gravitational-wave Observatory (LIGO) and the Virgo interferometer. We apply a baseline test of this method to the binary neutron star (BNS) merger GW170817 and find ${{\rm{H}}}_{0}={70}_{-18.0}^{+35.0}$ km s-1 Mpc-1 (maximum a posteriori and 68.3% highest density posterior interval) for a galaxy B-band luminosity threshold of ${L}_{B}\geqslant 0.001\,{L}_{B}^{* }$ with a correction for catalog incompleteness. Repeating the calculation for GW190814, we obtain ${{\rm{H}}}_{0}={67}_{-26.0}^{+41.0}$ km s-1 Mpc-1 and ${{\rm{H}}}_{0}={71}_{-30.0}^{+34.0}$ km s-1 Mpc-1 for ${L}_{B}\geqslant 0.001\,{L}_{B}^{* }$ and ${L}_{B}\geqslant 0.626\,{L}_{B}^{* }$ , respectively. Combining the posteriors for both events yields ${{\rm{H}}}_{0}={70}_{-18.0}^{+29.0}$ km s-1 Mpc-1, demonstrating the improvement on constraints when using multiple gravitational-wave events. We also confirm the results of other works that adopt this method, showing that increasing the LB threshold enhances the posterior structure and slightly shifts the distribution's peak to higher H0 values.We repeat the joint inference using the low-spin PhenomPNRT and the newly available combined (SEOBNRv4PHM + IMRPhenomPv3HM) posterior samples for GW170817 and GW190814, respectively, achieving a tighter constraint of ${{\rm{H}}}_{0}={69}_{-14.0}^{+29.0}$ km s-1 Mpc-1.

Keywords: gravitational waves; hubble constant; black holes; compact objects; neutron stars; bayesian statistics; posterior distribution
Detection of Interstellar HC4NC and an Investigation of Isocyanopolyyne Chemistry under TMC-1 Conditions

We report an astronomical detection of HC4NC for the first time in the interstellar medium with the Green Bank Telescope toward the TMC-1 molecular cloud with a minimum significance of 10.5σ. The total column density and excitation temperature of HC4NC are determined to be ${3.29}_{-1.20}^{+8.60}\times {10}^{11}$ cm-2 and ${6.7}_{-0.3}^{+0.3}\ {\rm{K}}$ , respectively, using Markov chain Monte Carlo analysis. In addition to HC4NC, HCCNC is distinctly detected whereas no clear detection of HC6NC is made. We propose that the dissociative recombination of the protonated cyanopolyyne, HC5NH+, and the protonated isocyanopolyyne, HC4NCH+, are the main formation mechanisms for HC4NC while its destruction is dominated by reactions with simple ions and atomic carbon. With the proposed chemical networks, the observed abundances of HC4NC and HCCNC are reproduced satisfactorily.

Keywords: astrochemistry; chemical abundances; interstellar medium; dark interstellar clouds; dense interstellar clouds; interstellar molecules
How Well Can We Measure the Stellar Mass of a Galaxy: The Impact of the Assumed Star Formation History Model in SED Fitting

The primary method for inferring the stellar mass (M*) of a galaxy is through spectral energy distribution (SED) modeling. However, the technique rests on assumptions such as the galaxy star formation history (SFH) and dust attenuation law that can severely impact the accuracy of derived physical properties from SED modeling. Here we examine the effect that the assumed SFH has on the stellar properties inferred from SED fitting by ground-truthing them against mock observations of high-resolution cosmological hydrodynamic galaxy formation simulations. Classically, SFHs are modeled with simplified parameterized functional forms, but these forms are unlikely to capture the true diversity of galaxy SFHs and may impose systematic biases with underreported uncertainties on results. We demonstrate that flexible nonparametric SFHs outperform traditional parametric forms in capturing variations in galaxy SFHs and, as a result, lead to significantly improved stellar masses in SED fitting. We find a decrease in the average bias of 0.4 dex with a delayed-τ model to a bias under 0.1 dex for the nonparametric model, though this is heavily dependent on the choice of prior for the nonparametric model. Similarly, using nonparametric SFHs in SED fitting results in increased accuracy in recovered galaxy star formation rates and stellar ages.

Keywords: astronomy data modeling; hydrodynamical simulations; stellar masses; galaxy properties; spectral energy distribution; radiative transfer simulations
Compact Radio Emission from Nearby Galaxies with Mid-infrared Nuclear Outbursts

We present 5.5 GHz observations with the Very Large Array of a sample of nearby galaxies with energetic nuclear outbursts at mid-infrared (MIR) bands. These observations reach a uniform depth down to a median rms of ∼10 μJy, representing one of the most sensitive searches for radio emission associated with nuclear transients. We detect radio emission in 12 out of 16 galaxies at a level of >5σ, corresponding to a detection rate of 75%. Such a high detection is remarkably different from previous similar searches in stellar tidal disruption events. The radio emission is compact and not resolved for the majority of sources on scales of ≲0"5 (<0.9 kpc at z < 0.1). We find that the possibility of the star formation contributing to the radio emission is low, but an active galactic nucleus (AGN) origin remains a plausible scenario, especially for sources that show evidence of AGN activity in their optical spectra. If the detections could represent radio emission associated with a nuclear transient phenomenon such as a jet or outflow, we could use the blast wave model by analogy with the gamma-ray burst afterglows to describe the evolution of radio light curves. In this context, the observations are consistent with a decelerating jet with an energy of ∼1051-52 erg viewed at 30°-60° off-axis at later times, suggesting that powerful jets may be ubiquitous among MIR-burst galaxies. Future continuous monitoring observations will be crucial to decipher the origin of radio emission through detections of potential flux and spectral evolution. Our results highlight the importance of radio observations to constrain the nature of nuclear MIR outbursts in galaxies.

Keywords: radio continuum emission; radio jets; dust continuum emission; surveys; tidal disruption; active galaxies
Unveiling MOA-2007-BLG-192: An M Dwarf Hosting a Likely Super-Earth

We present an analysis of high-angular-resolution images of the microlensing target MOA-2007-BLG-192 using Keck adaptive optics and the Hubble Space Telescope. The planetary host star is robustly detected as it separates from the background source star in nearly all of the Keck and Hubble data. The amplitude and direction of the lens–source separation allows us to break a degeneracy related to the microlensing parallax and source radius crossing time. Thus, we are able to reduce the number of possible binary-lens solutions by a factor of ∼2, demonstrating the power of high-angular-resolution follow-up imaging for events with sparse light-curve coverage. Following Bennett et al., we apply constraints from the high-resolution imaging on the light-curve modeling to find host star and planet masses of M host = 0.28 ± 0.04 M ☉ and at a distance from Earth of D L = 2.16 ± 0.30 kpc. This work illustrates the necessity for the Nancy Grace Roman Galactic Exoplanet Survey to use its own high-resolution imaging to inform light-curve modeling for microlensing planets that the mission discovers.

Keywords: exoplanets; gravitational microlensing; adaptive optics; high-resolution microlensing event imaging; observational astronomy; astronomy data modeling; hst photometry; astrometry
On the Use of Evidence and Goodness-of-fit Metrics in Exoplanet Atmosphere Interpretation

In exoplanet atmosphere analyses, a suite of retrievals, with and without different chemical components, is often run, with forward models generated across their parameter space. I discuss here potential pitfalls in the interpretation of the statistics of such setups, suggesting a few simple tests to consider when interpreting their results.

Keywords: exoplanet atmospheric composition; astrostatistics
Detection of Missing Baryons in Galaxy Groups with Kinetic Sunyaev-Zel'dovich Effect

We present the detection of the kinetic Sunyaev-Zel'dovich effect (kSZE) signals from groups of galaxies as a function of halo mass down to $\mathrm{log}({M}_{500}/{M}_{\odot })\sim 12.3$ using the Planck cosmic microwave background maps and stacking about 40,000 galaxy systems with known positions, halo masses, and peculiar velocities. The signals from groups of different mass are constrained simultaneously to take care of the projection effects of nearby halos. The total kSZE flux within halos estimated implies that the gas fraction in halos is about the universal baryon fraction, even in low-mass halos, indicating that the "missing baryons" are found. Various tests performed show that our results are robust against systematic effects, such as contamination by infrared/radio sources and background variations, beam size effects, and contributions from halo exteriors. Combined with the thermal Sunyaev-Zel'dovich effect, our results indicate that the "missing baryons" associated with galaxy groups are contained in warm-hot media with temperatures between 105 and 106 K.

Keywords: galaxy formation; galaxy evolution; galaxy dark matter halos; circumgalactic medium; extragalactic astronomy; galaxy environments; galaxy groups; galaxy clusters
3D Convection-resolving Model of Temperate, Tidally Locked Exoplanets

A large fraction of known terrestrial-size exoplanets located in the habitable zone of M-dwarfs are expected to be tidally locked. Numerous efforts have been conducted to study the climate of such planets, using in particular 3D global climate models (GCMs). One of the biggest challenges in simulating such an extreme environment is to properly represent the effects of sub-grid convection. Most GCMs use either a simplistic convective-adjustment parameterization or sophisticated (e.g., mass flux scheme) Earth-tuned parameterizations. One way to improve the representation of convection is to study convection using numerical convection-resolving models (CRMs), with a fine spatial resolution. In this study, we developed a CRM coupling the non-hydrostatic dynamical core Advanced Research Weather-Weather Research and Forecast model with the radiative transfer and cloud/precipitation models of the Laboratoire de Météorologie Dynamique generic climate model to study convection and clouds on tidally locked planets, with a focus on Proxima b. Simulations were performed for a set of three surface temperatures (corresponding to three different incident fluxes) and two rotation rates, assuming an Earth-like atmosphere. The main result of our study is that while we recover the prediction of GCMs that (low-altitude) cloud albedo increases with increasing stellar flux, the cloud feedback is much weaker due to transient aggregation of convection leading to low partial cloud cover.

Keywords: exoplanet atmospheres; atmospheric clouds
Galaxy and Mass Assembly (GAMA): A WISE Study of the Activity of Emission-line Systems in G23

We present a detailed study of emission-line systems in the Galaxy And Mass Assembly (GAMA) G23 region, making use of Wide-field Infrared Survey Explorer (WISE) photometry that includes carefully measured resolved sources. After applying several cuts to the initial catalog of ∼41,000 galaxies, we extract a sample of 9809 galaxies. We then compare the spectral diagnostic Baldwin, Philips & Terlevich (BPT) classification of 1154 emission-line galaxies (38% resolved in W1) to their location in the WISE color-color diagram, leading to the creation of a new zone for mid-infrared "warm" galaxies located 2&sgr; above the star-forming sequence, below the standard WISE active galactic nucleus (AGN) region. We find that the BPT and WISE diagrams agree on the classification for 85% and 8% of the galaxies as non-AGN (star-forming = SF) and AGN, respectively, and disagree on ∼7% of the entire classified sample. Thirty-nine percent of the AGNs (all types) are broad-line systems for which the [N II] and [Hα] fluxes can barely be disentangled, giving in most cases spurious [N II]/[Hα] flux ratios. However, several optical AGNs appear to be completely consistent with SF in WISE. We argue that these could be low-power AGNs, or systems whose hosts dominate the IR emission. Alternatively, given the sometimes high [O III] luminosity in these galaxies, the emission lines may be generated by shocks coming from super-winds associated with SF rather than AGN activity. Based on our findings, we have created a new diagnostic: [W1 - W2] versus [N II]/[Hα], which has the virtue of separating SF from AGNs and high-excitation sources. It classifies 3 to ∼5 times more galaxies than the classic BPT.

Keywords: galaxy evolution; agn host galaxies; infrared galaxies
Intermediate-mass Early-type Disk Galaxies in the Virgo Cluster. II. Near-Infrared Spectra and Evidence for Differences in Evolution

We discuss near-infrared (NIR) slit spectra of six early-type disk galaxies in the Virgo Cluster that were examined previously at visible/red wavelengths. Despite having similar intrinsic luminosities, colors, and morphologies, the NIR spectrophotometric properties of these galaxies indicate that they are not a homogeneous ensemble differing only in terms of luminosity-weighted age and metallicity. While the depth of the CO(2,0) band is consistent with the centers of these galaxies having solar or slightly sub-solar luminosity-weighted metallicities, galaxy-to-galaxy variations in the depth of the Na I 2.21 μm doublet are found, with Na I2.21 μm lines in three galaxies (NGC 4491, NGC 4584, and NGC 4620) that are deeper than those predicted for a solar chemical mixture and a solar-neighborhood mass function. In contrast, the Ca I2.26 μm triplet shows good galaxy-to-galaxy agreement but tends to be deeper than the model prediction. Considering the depth of the NaD lines, the deep Na I2.21 μm lines are tentatively attributed to a bottom-heavy mass function. This is counter to observed trends between mass function slope and velocity dispersion, and so the possibility of a super-solar [Na/Fe] is also discussed. Two of the three galaxies with deep Na I 2.21 μm (NGC 4584 and NGC 4620) have Sérsic exponents that are consistent with a classical bulge. As for NGC 4491, its central NIR spectrum contains prominent emission lines. The relative strengths of Brγ and H2S(1), the presence of [Fe II] emission, and the mid-infrared spectral-energy distribution are all consistent with intense recent star formation near the center of that galaxy. The NIR spectrum of NGC 4584 is devoid of line emission in the NIR, suggesting that star formation does not power the emission detected at visible wavelengths from that galaxy. Wavelengths that contain the Ballick-Ramsey C2 band at 1.76 μm are matched by moderately metal-poor E-MILES model spectra with an age of 2 Gyr. The radial age trends in these galaxies are in the opposite sense to those in late-type disk galaxies, and it is concluded that they have evolved in a cluster environment for at least several Gyr.

This research makes use of the Virgo cluster galaxy database of McDonald et al. (2011).

This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Keywords: lenticular galaxies; galaxy evolution; disk galaxies; quenched galaxies
Blue Large-amplitude Pulsators: The Possible Surviving Companions of Type Ia Supernovae

The single degenerate (SD) model, one of the leading models for the progenitors of Type Ia supernovae (SNe Ia), predicts that there should be binary companions that survive the supernova explosion, which, in principle, should be detectable in the Galaxy. The discovery of such surviving companions could therefore provide conclusive support for the SD model. Several years ago, a new type of mysterious variable was discovered, the so-called blue large-amplitude pulsators (BLAPs). Here we show that all the properties of BLAPs can be reasonably well reproduced if they are indeed such surviving companions, in contrast to other proposed channels. This suggests that BLAPs could potentially be the long-sought surviving companions of SNe Ia. Our model also predicts a new channel for forming single hot subdwarf stars, consistent with a small group in the present sample of hot subdwarf stars.

Keywords: type ia supernovae; white dwarf stars; variable stars; supernova remnants