adsabs/SciX_UAT_keywords huggingface dataset:
HST Grism-derived Forecasts for Future Galaxy Redshift Surveys

The mutually complementary Euclid and Roman galaxy redshift surveys will use Hα- and [O III]-selected emission-line galaxies (ELGs) as tracers of the large-scale structure at 0.9 ≲ z ≲ 1.9 (Hα) and 1.5 ≲ z ≲ 2.7 ([O III]). It is essential to have a reliable and sufficiently precise knowledge of the expected numbers of Hα-emitting galaxies in the survey volume in order to optimize these redshift surveys for the study of dark energy. Additionally, these future samples of ELGs will, like all slitless spectroscopy surveys, be affected by a complex selection function that depends on galaxy size and luminosity, line equivalent width (EW), and redshift errors arising from the misidentification of single ELGs. Focusing on the specifics of the Euclid survey, we combine two slitless spectroscopic WFC3-IR data sets—3D-HST+AGHAST and the WFC3 Infrared Spectroscopic Parallel survey—to construct a Euclid-like sample that covers an area of 0.56 deg2 and includes 1277 ELGs. We detect 1091 (∼3270 deg-2) Hα+[N II]-emitting galaxies in the range 0.9 ≤ z ≤ 1.6 and 162 (∼440 deg-2) [O III] λ5007 emitters over 1.5 ≤ z ≤ 2.3 with line fluxes ≥2 × 10-16 erg s-1 cm-2. The median of the Hα+[N II] EW distribution is ∼250 Å, and the effective radii of the continuum and Hα+[N II] emission are correlated with a median of ∼0"38 and significant scatter (σ ∼ 0"2-0"35). Finally, we explore the prevalence of redshift misidentification in future Euclid samples, finding potential contamination rates of ∼14%-20% and ∼6% down to 2 × 10-16 erg s-1 cm-2 and 6 × 10-17 erg s-1 cm-2, respectively, although with increased wavelength coverage these percentages drop to nearly zero.

Keywords: emission line galaxies; spectroscopy; redshift surveys
Thermal Properties of 1847 WISE-observed Asteroids

We present new thermophysical model fits of 1847 asteroids, deriving thermal inertia, diameter, and Bond and visible geometric albedo. We use thermal flux measurements obtained by the Wide-field Infrared Survey Explorer (WISE) during its fully cryogenic phase, when both the 12 μm (W3) and 22 μm (W4) bands were available. We take shape models and spin information from the Database of Asteroid Models from Inversion Techniques (DAMIT) and derive new shape models through lightcurve inversion and combining WISE photometry with existing DAMIT lightcurves. When we limit our sample to the asteroids with the most reliable shape models and thermal flux measurements, we find broadly consistent thermal inertia relations with recent studies. We apply fits to the diameters D (km) and thermal inertia Γ (J m-2 s-0.5 K-1) normalized to 1 au with a linear relation of the form $\mathrm{log}[{\rm{\Gamma }}]=\alpha +\beta \mathrm{log}[D]$ , where we find α = 2.667 ± 0.059 and β = -0.467 ± 0.044 for our sample alone and α = 2.509 ± 0.017 and β = -0.352 ± 0.012 when combined with other literature estimates. We find little evidence of any correlation between rotation period and thermal inertia, owing to the small number of slow rotators to consider in our sample. While the large uncertainties on the majority of our derived thermal inertia only allow us to identify broad trends between thermal inertia and other physical parameters, we can expect a significant increase in high-quality thermal flux measurements and asteroid shape models with upcoming infrared and wide-field surveys, enabling even more thermophysical modeling of higher precision in the future.

Keywords: asteroids; main belt asteroids; astronomy data modeling
A Comparison of Stellar Kinematics Derived from Two Gemini NIFS Reduction Pipelines

The Gemini Near-infrared Integral Field Spectrograph (NIFS) reduction pipeline is widely used to reduce NIFS data. However, there are critical known limitations. A new NIFS reduction pipeline has recently been developed and solves several of these problems. We present a comparison of stellar kinematics derived from the new and old data reduction pipelines, as well as recommendations for optimal NIFS data reduction.

Keywords: stellar kinematics; astronomy data reduction; agn host galaxies
Line Oscillator Strengths for the {{{c}}_{4}}({') 1}{{{\Sigma }}_{{u}}}(+}(4)-{{X}}({1)) {{{\Sigma }}_{{g}}}(+}(0\mbox{-) 7) Absorption Bands of N2

Theoretical absorption oscillator strengths for rotational lines of the ${{{\rm{c}}}_{4}}^{{\prime} 1}{{{\rm{\Sigma }}}_{{\rm{u}}}}^{+}(4)$ - ${{\rm{X}}}^{1}{{{\rm{\Sigma }}}_{{\rm{g}}}}^{+}$ (0-7) bands of N2, which are relevant to analyze the spectra of the atmospheres of the Earth, Titan, and Mars, are reported. The known interaction between the ${{{\rm{c}}}_{4}}^{{\prime} 1}{{{\rm{\Sigma }}}_{{\rm{u}}}}^{+}(4)$ and ${{{\rm{c}}}_{3}}^{1}{{{\rm{\Pi }}}_{{\rm{u}}}}^{+}(4)$ Rydberg states and the ${{\rm{b}}}^{{\prime} 1}{{{\rm{\Sigma }}}_{{\rm{u}}}}^{+}(13)$ valence state has been dealt with through an appropriate rovibronic energy matrix. Deviations in the intensity distribution of the rotational lines from considerations based on Hönl-London factors have been found for each of the studied bands. Emission branching ratios for the above bands and lifetimes of the rotational levels of the v = 4 level of the ${{{\rm{c}}}_{4}}^{{\prime} 1}{{{\rm{\Sigma }}}_{{\rm{u}}}}^{+}$ state are also reported.

Keywords: molecular spectroscopy; line intensities; radiative processes
GASP. XXXII. Measuring the Diffuse Ionized Gas Fraction in Ram-pressure-stripped Galaxies

The diffuse ionized gas (DIG) is an important component of the interstellar medium, and it can be affected by many physical processes in galaxies. Measuring its distribution and contribution in emission allows us to properly study both its ionization and star formation in galaxies. Here, we measure for the first time the DIG emission in 38 gas-stripped galaxies in local clusters drawn from the GAs Stripping Phenomena in galaxies with the MUSE survey (GASP). These galaxies are at different stages of stripping. We also compare the DIG properties to those of 33 normal galaxies from the same survey. To estimate the DIG fraction (CDIG) and derive its maps, we combine the attenuation-corrected Hα surface brightness with the [S II]/Hα line ratio. Our results indicate that we cannot use either a single Hα or [S II]/Hα value, or a threshold in equivalent width of Hα emission line to separate spaxels dominated by DIG and non-DIG emission. Assuming a constant surface brightness of the DIG across galaxies underestimates CDIG. Contrasting stripped and nonstripped galaxies, we find no clear differences in CDIG. The DIG emission contributes between 20% and 90% of the total integrated flux and does not correlate with the galactic stellar mass and star formation rate (SFR). The CDIG anticorrelates with the specific SFR, which may indicate an older (>108 yr) stellar population as the ionizing source of the DIG. The DIG fraction shows anticorrelations with the SFR surface density, which could be used for a robust estimation of integrated CDIG in galaxies.

Keywords: galaxy clusters; galaxy groups; interstellar medium
Confrontation of Observation and Theory: High-frequency QPOs in X-Ray Binaries, Tidal Disruption Events, and Active Galactic Nuclei

We compile observations of high-frequency quasi-periodic oscillations (QPOs) around black holes, both stellar and supermassive, and compare their positions in the parameter space of black hole mass, spin, and oscillation frequency. We find that supermassive black holes occupy a separate region of parameter space than stellar, and further, that QPOs seen around tidal disruption events rather than Seyfert-type active galactic nuclei (AGN) occupy an entirely different space. We then compare these results to the orbital resonance, diskoseismic, warped disk, and disk-jet coupling theoretical models for the origin of high-frequency QPOs. We find that while oscillations around stellar mass black holes are generally consistent with the above models, supermassive black holes are decidedly not. Oscillations seen in tidal disruption events are consistent with oscillations near the frequency of the innermost stable circular orbit, while QPOs in AGN are not accounted for by any of the physical models in consideration. This indicates that despite the scale invariance of accretion processes implied by a decades-wide correlation between QPO frequency and black hole mass, any theory of high-frequency QPOs must relate the frequency to more than just the mass and spin.

Keywords: active galactic nuclei; black holes; x-ray binary stars; high energy astrophysics; tidal disruption; general relativity
The Effect of Multiple Low-mass Flybys Can Preserve the Orbit of Neptune-like Objects in Slightly Perturbed Orbits in Star Formation Clusters

The objective of this work is focused on solving the problem in the regular theory where the strong effects of single impacts on proplanetary particles in the early stages of the Solar system can noticeably perturb the orbit of inner planets such as Neptune. As a first-approach solution, I propose that multiple low-mass flybys can produce the observed orbit of a Neptune-like particle. I calculated the effects of four subsequent flybys to know the difference between their effects and the effect of a massive encounter. The effects of multiple low-mass impacts deliver lower eccentricities and inclinations of the planetary particle compared to the result produced by the single encounter.

Keywords: debris disks; orbits; protoplanetary disks; stellar dynamics
An Observational Study of a "Rosetta Stone" Solar Eruption

This Letter reports observations of an event that connects all major classes of solar eruptions: those that erupt fully into the heliosphere versus those that fail and are confined to the Sun, and those that eject new flux into the heliosphere, in the form of a flux rope, versus those that eject only new plasma in the form of a jet. The event originated in a filament channel overlying a circular polarity inversion line and occurred on 2016 March 13 during the extended decay phase of the active region designated NOAA 12488/12501. The event was especially well observed by multiple spacecraft and exhibited the well-studied null-point topology. We analyze all aspects of the eruption using Solar Dynamics Observatory Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager, Solar-Terrestrial Relations Observatory Extreme Ultraviolet Imager, and Solar and Heliospheric Observatory Large Angle and Spectrometric Coronagraph (SOHO LASCO) imagery. One section of the filament undergoes a classic failed eruption with cool plasma subsequently draining onto the section that did not erupt, but a complex structured coronal mass ejection/jet is clearly observed by SOHO/LASCO C2 shortly after the failed filament eruption. We describe in detail the slow buildup to eruption, the lack of an obvious trigger, and the immediate reappearance of the filament after the event. The unique mixture of major eruption properties observed during this event places severe constraints on the structure of the filament channel field and, consequently, on the possible eruption mechanism.

Keywords: solar coronal holes; solar corona; solar coronal mass ejections; solar magnetic reconnection; solar magnetic fields
Variable Stars in Local Group Galaxies. VI. The Isolated Dwarfs VV 124 and KKr 25

We present the discovery of variable stars in two isolated dwarf galaxies in the outskirts of the Local Group, VV 124 and KKr 25, using observations with the Hubble Space Telescope. VV 124 hosts stellar populations with a wide range of ages (>10 Gyr until the present) and therefore we find all types of classical pulsators. In VV 124, we detect a total of 771 variable stars, including 78 classical Cepheids, 10 anomalous Cepheids, one Type II Cepheid, 678 RR Lyrae stars, and four eclipsing binaries. In KKr 25, we find 25 anomalous Cepheids, 46 RR Lyrae stars, and no classical Cepheids, thus the galaxy does not have a strong young population. A comparison of the variables with evolutionary tracks suggests that both galaxies may contain an intrinsic spread in metallicity, but overall are fairly metal-poor. We also present detailed simulations, which have been designed to estimate the completeness of our variable catalog. Particularly in the cases for which the observations are not deep enough to reach the main-sequence turnoff, such as the more distant Local Group dwarf galaxies, the techniques developed here can be used together with relatively shallow color-magnitude diagrams to inform on the nature of galactic populations over the full range of ages.

Keywords: dwarf galaxies; dwarf spheroidal galaxies; pulsating variable stars; rr lyrae variable stars; cepheid variable stars; anomalous cepheid variable stars; population ii cepheid variable stars
Loose Ends for the Exomoon Candidate Host Kepler-1625b

The claim of an exomoon candidate in the Kepler-1625b system has generated substantial discussion regarding possible alternative explanations for the purported signal. In this work, we examine these possibilities in detail. First, the effect of more flexible trend models is explored, and we show that sufficiently flexible models are capable of attenuating the signal -- although this is an expected byproduct of invoking such models. We also explore trend models using x- and y-centroid positions, and show that there is no data-driven impetus to adopt such models over temporal ones. We quantify the probability that the 500 ppm moon-like dip could be caused by a Neptune-sized transiting planet to be <0.75%. We show that neither autocorrelation, Gaussian processes, nor a Lomb-Scargle periodogram are able to recover a stellar rotation period, demonstrating that K1625 is a quiet star with periodic behavior <200 ppm. Through injection and recovery tests, we find that the star does not exhibit a tendency to introduce false-positive dip-like features above that of pure Gaussian noise. Finally, we address a recent reanalysis by Kreidberg et al. and show that the difference in conclusions is not from differing systematics models but rather the reduction itself. We show that their reduction exhibits, in comparison to the original analysis: (i) slightly higher intraorbit and post-fit residual scatter, (ii) ≃900 ppm larger flux offset at the visit change, (iii) ≃2 times larger y-centroid variations, and (iv) ≃3.5 times stronger flux-centroid correlation coefficient. These points could be explained by larger systematics in their reduction, potentially impacting their conclusions.

Keywords: natural satellites (extrasolar); irregular natural satellites (extrasolar); exoplanet detection methods
The Persistent Radio Jet Coupled to Hard X-Rays in the Soft State of Cyg X-1

We study long-term radio/X-ray correlations in Cyg X-1. We find the persistent existence of a compact radio jet in its soft state. This represents a new phenomenon in black hole binaries, in addition to compact jets in the hard state and episodic ejections of ballistic blobs in the intermediate state. While the radio emission in the hard state is strongly correlated with both the soft and hard X-rays, the radio flux in the soft state is not directly correlated with the flux of the dominant disk blackbody in soft X-rays, but instead it is lagged by about 100 days. We interpret the lag as occurring in the process of advection of the magnetic flux from the donor through the accretion disk. On the other hand, the soft-state radio flux is very tightly correlated with the hard X-ray, 15-50 keV, flux without a measurable lag and at the same rms. This implies that the X-ray-emitting disk corona and the soft-state jet are powered by the same process, probably magnetically.

Keywords: magnetic fields; x-ray sources; stellar jets; non-thermal radiation sources; x-ray binary stars; radio sources
Searching for Exotic Cores with Binary Neutron Star Inspirals

We study the feasibility of detecting exotic cores in merging neutron stars with ground-based gravitational-wave detectors. We focus on models with a sharp nuclear/exotic matter interface, and assume a uniform distribution of neutron stars in the mass range [1, 2] M⊙. We find that the existence of exotic cores can be confirmed at the 70% confidence level with as few as several tens of detections. Likewise, with such a sample, we find that some models of exotic cores can be excluded with high confidence.

Keywords: nuclear astrophysics; gravitational waves
How Dense of a Circumstellar Medium Is Sufficient to Choke a Jet?

The progenitor stars of stripped-envelope high-velocity supernovae (Ic-BL SNe) can explode inside a dense circumstellar medium (CSM) that extends out to many times the progenitor radius. This complicates the question of whether all Ic-BL SNe harbor a jet, which can tunnel through the star and be viewed on-axis as a long-duration gamma-ray burst (GRB). More specifically, a sufficiently dense CSM might "choke" the jet, redistributing its energy quasi-spherically. In this study, we numerically calculate the CSM density necessary for jet choking. For typical GRBs, we determine the jet is not choked in the CSM unless $\rho {r}^{2}\gt 4\times {10}^{19}\,{\rm{g}}\,{\mathrm{cm}}^{-1};$ this requires several solar masses of CSM to be situated within 1013 cm of the progenitor, a much higher density than any CSM observed. We conclude that typical GRB jets are not choked in the CSM. However, in many cases the CSM has sufficient mass to decelerate the jet to a modest Lorentz factor (Γ ∼ 10), which should lead to a long coasting phase for the jet, observable as a long plateau (potentially up to a few days) in the afterglow light curve. For extreme cases of low-energy GRBs in a high-mass CSM, the jet will decelerate to nonrelativistic velocities, causing it to spread modestly to a larger opening angle (θj ≈ 20°) before breaking out of the CSM. Even in these extreme examples, the jet does not have time to redistribute its energy quasi-spherically in the CSM before breakout.

Keywords: circumstellar matter; supernovae; relativistic jets; relativistic fluid dynamics; gamma-ray bursts
LAMA: LAMOST Medium-Resolution Spectral Analysis Pipeline

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has obtained more than 23 million spectra, opening an unprecedented opportunity to study stellar physics, as well as the formation and evolution of our Milky Way. In order to obtain the accurate stellar parameters, we develop a LAMOST Medium-Resolution Spectral Analysis Pipeline (LAMA), which estimates the stellar parameters from the LAMOST medium-resolution spectra, including the effective temperature (T eff), surface gravity ( ), metallicity ([Fe/H]), radial velocity, and rotational velocity ( ). LAMA estimates these parameters utilizing the template-matching method. The comparison between our results and those from the high-resolution ones, including APOGEE, GALAH, and PASTEL, shows no obvious bias, indicating the reliability of our results. The accuracy of T eff and [Fe/H] can reach 75 K and 0.12 dex, respectively, for the LAMOST Medium-Resolution Spectroscopic Survey (MRS) spectra with a signal-to-noise ratio higher than 10. For dwarfs, the uncertainty of is around 0.17 dex, while, for giants, it ranges from 0.18 to 0.30 dex, with the errors decreasing as increases. Using LAMA for the LAMOST-MRS spectra, we estimate the stellar parameters of 497,412 stars. This sample will be very helpful for investigating the formation and evolution of our Galaxy.

Keywords: catalogs; surveys; fundamental parameters of stars; spectroscopy
The Complete CEERS Early Universe Galaxy Sample: A Surprisingly Slow Evolution of the Space Density of Bright Galaxies at z ∼ 8.5–14.5

We present a sample of 88 candidate z ∼ 8.5–14.5 galaxies selected from the completed NIRCam imaging from the Cosmic Evolution Early Release Science survey. These data cover ∼90 arcmin2 (10 NIRCam pointings) in six broadband imaging filters and one medium-band imaging filter. With this sample we confirm at higher confidence early JWST conclusions that bright galaxies in this epoch are more abundant than predicted by most theoretical models. We construct the rest-frame ultraviolet luminosity functions at z ∼ 9, 11, and 14 and show that the space density of bright (M UV = ‑20) galaxies changes only modestly from z ∼ 14 to z ∼ 9, compared to a steeper increase from z ∼ 8 to z ∼ 4. While our candidates are photometrically selected, spectroscopic follow-up has now confirmed 13 of them, with only one significant interloper, implying that the fidelity of this sample is high. Successfully explaining the evidence for a flatter evolution in the number densities of UV-bright z > 10 galaxies may thus require changes to the dominant physical processes regulating star formation. While our results indicate that significant variations of dust attenuation with redshift are unlikely to be the dominant factor at these high redshifts, they are consistent with predictions from models that naturally have enhanced star formation efficiency and/or stochasticity. An evolving stellar initial mass function could also bring model predictions into better agreement with our results. Deep spectroscopic follow-up of a large sample of early galaxies can distinguish between these competing scenarios.

Keywords: early universe; galaxy formation; galaxy evolution; luminosity function
A NOEMA Molecular Line Scan of the Hubble Deep Field North: Improved Constraints on the CO Luminosity Functions and Cosmic Density of Molecular Gas

We present measurements of the CO luminosity functions (LFs) and the evolution of the cosmic molecular gas density out to z ~ 6 based on an 8.5 arcmin2 spectral scan survey at 3 mm of the iconic Hubble Deep Field North (HDF-N) observed with the NOrthern Extended Millimeter Array (NOEMA). We use matched filtering to search for line emission from galaxies and determine their redshift probability distributions exploiting the extensive multiwavelength data for the HDF-N. We identify the seven highest-fidelity sources as CO emitters at 1 < z < 6, including the well-known submillimeter galaxy HDF 850.1 at z = 5.18. Four high-fidelity 3 mm continuum sources are found to be radio galaxies at z ≤ 1, plus HDF 850.1. We constrain the CO LFs in the HDF-N out to z ~ 6, including a first measurement of the CO(5-4) LF at <z> = 5.0. The relatively large area and depth of the NOEMA HDF-N survey extends the existing LFs at 1 < z < 4 above the knee, yielding a somewhat lower density by 0.15-0.4 dex at the overlap region for the CO(2-1) and CO(3-2) transitions, attributed to cosmic variance. We perform a joint analysis of the CO LFs in the HDF-N and Hubble Ultra Deep Field from ASPECS, finding that they can be well described by a single Schechter function. The evolution of the cosmic molecular gas density from a joint analysis is in good agreement with earlier determinations. This implies that the impact of cosmic field-to-field variance on the measurements is consistent with previous estimates, adding to the challenges for simulations that model galaxies from first principles.

Keywords: molecular gas; galaxy evolution; luminosity function; high-redshift galaxies; interstellar medium; co line emission; spectroscopy