adsabs/SciX_UAT_keywords huggingface dataset:
Evolution of the Mass-Metallicity Relation from Redshift z ≈ 8 to the Local Universe

A tight positive correlation between the stellar mass and the gas-phase metallicity of galaxies has been observed at low redshifts. The redshift evolution of this correlation can strongly constrain theories of galaxy evolution. The advent of JWST allows probing the mass-metallicity relation at redshifts far beyond what was previously accessible. Here we report the discovery of two emission line galaxies at redshifts 8.15 and 8.16 in JWST NIRCam imaging and NIRSpec spectroscopy of targets gravitationally lensed by the cluster RX J2129.4+0005. We measure their metallicities and stellar masses along with nine additional galaxies at 7.2 < z spec < 9.5 to report the first quantitative statistical inference of the mass-metallicity relation at z ≈ 8. We measure ~0.9 dex evolution in the normalization of the mass-metallicity relation from z ≈ 8 to the local universe; at a fixed stellar mass, galaxies are 8 times less metal enriched at z ≈ 8 compared to the present day. Our inferred normalization is in agreement with the predictions of FIRE simulations. Our inferred slope of the mass-metallicity relation is similar to or slightly shallower than that predicted by FIRE or observed at lower redshifts. We compare the z ≈ 8 galaxies to extremely low-metallicity analog candidates in the local universe, finding that they are generally distinct from extreme emission line galaxies or "green peas," but are similar in strong emission line ratios and metallicities to "blueberry galaxies." Despite this similarity, at a fixed stellar mass, the z ≈ 8 galaxies have systematically lower metallicities compared to blueberry galaxies.

Keywords: galaxy evolution; galaxy chemical evolution; chemical abundances; metallicity; high-redshift galaxies
Discovery of the Tadpole Molecular Cloud near the Galactic Nucleus

In this paper, we report the discovery of an isolated, peculiar compact cloud with a steep velocity gradient at 2.'6 northwest of Sgr A*. This "Tadpole" molecular cloud is unique owing to its characteristic head-tail structure in the position-velocity space. By tracing the CO J = 3-2 intensity peak in each velocity channel, we noticed that the kinematics of the Tadpole can be well reproduced by a Keplerian motion around a point-like object with a mass of 1 × 105 M ⊙. Changes in line intensity ratios along the orbit are consistent with the Keplerian orbit model. The spatial compactness of the Tadpole and absence of bright counterparts in other wavelengths indicate that the object could be an intermediate-mass black hole.

Keywords: molecular clouds; interstellar medium; galactic center
The Lyman Continuum Escape Fraction of Galaxies and AGN in the GOODS Fields

We present our analysis of the Lyman continuum (LyC) emission and escape fraction of 111 spectroscopically verified galaxies with and without active galactic nuclei (AGN) from 2.26 < z < 4.3. We extended our ERS sample from Smith et al. with 64 galaxies in the GOODS North and South fields using WFC3/UVIS F225W, F275W, and F336W mosaics we independently drizzled using the HDUV, CANDELS, and UVUDF data. Among the 17 AGN from the 111 galaxies, one provided a LyC detection in F275W at ${m}_{\mathrm{AB}}$ = 23.19 mag (signal-to-noise ratio, S/N, ≃ 133) and GALEX NUV at ${m}_{\mathrm{AB}}$ = 23.77 mag (S/N ≃ 13). We simultaneously fit SDSS and Chandra spectra of this AGN to an accretion disk and Comptonization model, and find ${f}_{\mathrm{esc}}$ values of ${f}_{\mathrm{esc}}^{{\rm{F}}275{\rm{W}}}\simeq {28}_{-4}^{+20} \% $ and ${f}_{\mathrm{esc}}^{\mathrm{NUV}}\simeq {30}_{-5}^{+22} \% $ . For the remaining 110 galaxies, we stack image cutouts that capture their LyC emission using the F225W, F275W, and F336W data of the GOODS and ERS samples, and both combined, as well as subsamples of galaxies with and without AGN, and all galaxies. We find the stack of 17 AGN dominate the LyC production from $\langle z\rangle $ ≃ 2.3-4.3 by a factor of ∼10 compared to all 94 galaxies without AGN. While the IGM of the early universe may have been reionized mostly by massive stars, there is evidence that a significant portion of the ionizing energy came from AGN.

Keywords: high-redshift galaxies; ultraviolet astronomy; active galactic nuclei; reionization
Peak Temperatures of Large Solar X-Ray Flares and Associated CME Speeds and Widths

We recently repeated an earlier analysis by Garcia showing that large (≥M3.0) solar X-ray flares associated with solar energetic particle (SEP) events have significantly lower peak X-ray flux ratios R = (0.04-0.5 nm)/(0.1-0.8 nm), proxies for flare peak temperatures, than those without SEP events. As we expect SEP events to be produced by shocks ahead of fast coronal mass ejections (CMEs), a smaller R for an X-ray flare of a given peak flux Fp should also be more likely to be accompanied by a fast (Vcme > 1000 km s-1) CME. We confirm this expectation, examine the role played by the ratios R in correlations between Fp and CME speeds Vcme, and then compare CME widths W, Vcme, and R with each other. We consider an apparent conflict between a global scaling model of eruptive events showing Vcme scaling with higher R and our confirmation that the Garcia analysis implies that faster CMEs are associated with flares of lower R. The R values are examined for 16 large flares of the well-studied AR 12192, for which nearly all flares had no associated CMEs. Those flares share the same high values of R as other active region (AR) flares with no CMEs. We also find that small (<M3.0) flares of filament eruptions leading to SEP events share the lower R values of larger flares with fast CMEs.

Keywords: solar flares; solar coronal mass ejections; solar coronal mass ejection shocks; solar x-ray flares; solar flare spectra; solar active regions
Gravitational Wave Sources in Our Galactic Backyard: Predictions for BHBH, BHNS, and NSNS Binaries Detectable with LISA

Future searches for gravitational waves from space will be sensitive to double compact objects in our Milky Way. We present new simulations of the populations of double black holes (BHBHs), BH neutron stars (BHNSs), and double neutron stars (NSNSs) that will be detectable by the planned space-based gravitational-wave detector called Laser Interferometer Space Antenna (LISA). For our estimates, we use an empirically informed model of the metallicity-dependent star formation history of the Milky Way. We populate it using an extensive suite of binary population-synthesis predictions for varying assumptions relating to mass transfer, common-envelope, supernova kicks, remnant masses, and wind mass-loss physics. For a 4(10) yr LISA mission, we predict between 30-370(50-550) detections over these variations, out of which 6-154 (9-238) are BHBHs, 2-198 (3-289) are BHNSs, and 3-35 (4-57) are NSNSs. We expect that about 50% (60%) can be distinguished from double white dwarf sources based on their mass or eccentricity and localization. Specifically, for about 10% (15%), we expect to be able to determine chirp masses better than 10%. For 13% (13%), we expect sky-localizations better than 1°. We discuss how the variations in the physics assumptions alter the distribution of properties of the detectable systems, even when the detection rates are unchanged. We further discuss the possibility of multimessenger observations of pulsar populations with the Square Kilometre Array and assess the benefits of extending the LISA mission.

Keywords: gravitational waves; gravitational wave detectors; compact objects; neutron stars; stellar mass black holes; binary stars; pulsars; stellar evolution
A Method for the Estimation of f- and p-mode Parameters and Rotational Splitting Coefficients from Un-averaged Solar Oscillation Power Spectra

We present a new methodology for the fitting of the peaks in solar oscillation power spectra that is equally well-suited for the estimation of low-, medium, and high-degree f- and p-mode parameters and frequency-splitting coefficients. The method can provide accurate input data over a wide portion of the dispersion plane for both structural and rotational inversions. This method, which we call the Multiple-Peak, Tesseral-Spectrum (MPTS) method, operates directly upon of all of the modes in a multiplet (n, l) of radial order n and degree l, and employs a fitting profile that consists of the sum of numerous individual overlapping profiles whose relative amplitudes are determined by the leakage matrix appropriate to the targeted mode. Hence, 2l + 1 sets of modal parameters are obtained simultaneously for each multiplet (n, l). By fitting an appropriate polynomial to the run of the fitted frequencies versus the azimuthal order, frequency-splitting coefficients are also obtained for the same multiplet. Using power spectra obtained from the 66 day long 2010 MDI Dynamics Run, we present sample structural and rotational inversions that employed frequencies and frequency-splitting coefficients from modes in the degree range of 0-1000 and the frequency range of 965-4600 μHz. The structural inversion confirms evidence for a pronounced departure of the sound speed in the outer solar convection zone from the radial sound-speed profile contained in Model S of Christensen-Dalsgaard and his collaborators that we obtained previously using a different fitting method.

Keywords: the sun; helioseismology; astronomy data analysis
Coronal Abundances in an Active Region: Evolution and Underlying Chromospheric and Transition Region Properties

The element abundances in the solar corona and solar wind are often different from those of the solar photosphere, typically with a relative enrichment of elements with low first ionization potential (FIP effect). Here, we study the spatial distribution and temporal evolution of the coronal chemical composition in an active region (AR) over about 10 days, using Hinode/EIS spectra, and we also analyze coordinated IRIS observations of the chromospheric and transition region emission to investigate any evidence of the footprints of the FIP effect in the lower atmosphere. To derive the coronal abundances, we use a spectral inversion method recently developed for the MUSE investigation. We find that, in the studied active region (AR 12738), the coronal FIP bias, as diagnosed by the Si/S abundance ratio, presents significant spatial variations, with its highest values (~2.5-3.5) in the outflow regions at the boundary of the AR, but typically modest temporal variability. Some moss regions and some regions around the AR sunspot show enhanced FIP bias (~2-2.5) with respect to the AR core, which has only a small FIP bias of ~1.5. The FIP bias appears most variable in these moss regions. The IRIS observations reveal that the chromospheric turbulence, as derived from IRIS2 inversions of the Mg II spectra, is enhanced in the outflow regions characterized by the high FIP bias, providing significant new constraints to both models aimed at explaining the formation of AR outflows and models of chemical fractionation.

Keywords: active solar corona; solar coronal heating; solar corona; solar chromosphere; solar transition region; solar extreme ultraviolet emission; solar ultraviolet emission; solar physics; solar abundances
A Study about the Secular Evolution of the Hierarchical Three-body Problem Using the Numerical Integrator TIDES

The hierarchical three-body problem is one of the classical issues of celestial mechanics, but recently it has regained importance due to its applications to new scenarios, like compact objects and exoplanets. In this paper we realize a computational study of this problem using the TIDES software package, which is applied not only to a set of theoretical cases but also to actual stellar systems. The characteristics of the Taylor series integration method, used by TIDES, permit the confirmation of the appearance of the Lidov-Kozai cycles in the case of high mutual inclinations. In addition, a historical review of this problem is included.

Keywords: celestial mechanics; three-body problem; multiple stars
CoSHA: Code for Stellar Properties Heuristic Assignment-for the MaStar Stellar Library

We introduce COSHA: a Code for Stellar properties Heuristic Assignment. In order to estimate the stellar properties, COSHA implements a Gradient Tree Boosting algorithm to label each star across the parameter space (T eff, $\mathrm{log}g$ , [Fe/H], and [α/Fe]). We use COSHA to estimate the stellar atmospheric parameters of 22,000 unique stars in the MaNGA Stellar Library (MaStar). To quantify the reliability of our approach, we run internal tests, using both the Göttingen Stellar Library (a theoretical library) and the first data release of MaStar, and external tests, by comparing the resulting distributions in the parameter space with the APOGEE estimates of the same properties. In summary, our parameter estimates span the ranges T eff = [2900, 12,000] K, $\mathrm{log}g=[-0.5,5.6]$ , [Fe/H] = [-3.74, 0.81], and α M = [-0.22, 1.17]. We report internal (external) uncertainties of the properties of ${\sigma }_{{T}_{\mathrm{eff}}}\sim 43(240)$ K, ${\sigma }_{\mathrm{log}g}\sim 0.2(0.4)$ , σ [Fe/H] ~ 0.16(0.24), and σ [α/Fe] ~ 0.09(0.08). These uncertainties are comparable to those of other methods with similar objectives. Despite the fact that COSHA is not aware of the spatial distributions of these physical properties in the Milky Way, we are able to recover the main trends known in the literature. The catalog of physical properties for MaStar can be accessed online.

Keywords: stellar properties; astrostatistics
First Images of the Protoplanetary Disk around PDS 201

Scattered light imaging has revealed nearly a dozen circumstellar disks around young Herbig Ae/Be stars—enabling studies of structures in the upper disk layers as potential signs of ongoing planet formation. We present the first images of the disk around the variable Herbig Ae star PDS 201 (V* V351 Ori) and an analysis of the images and spectral energy distribution through 3D Monte Carlo radiative transfer simulations and forward modeling. The disk is detected in three data sets with the Large Binocular Telescope Interferometer/Large Binocular Telescope mid-infrared camera at the Large Binocular Telescope, including direct observations in the Ks and L' filters, and an L' observation with the 360° vector apodizing phase plate coronagraph. The scattered light disk extends to a very large radius of ∼250 au, which places it among the largest of such disks. Exterior to the disk, we establish detection limits on substellar companions down to ∼5 MJup at ≳1"5 (≳500 au), assuming the Baraffe et al. models. The images show a radial gap extending to ∼0"4 (∼140 au at a distance of 340 pc) that is also evident in the spectral energy distribution. The large gap is a possible signpost of multiple high-mass giant planets at orbital distances (∼60-100 au) that are unusually massive and widely separated compared to those of planet populations previously inferred from protoplanetary disk substructures.

Keywords: protoplanetary disks; exoplanets; variable stars; early-type variable stars
Measurements of the Hubble Constant: Tensions in Perspective

Measurement of the distances to nearby galaxies has improved rapidly in recent decades. The ever-present challenge is to reduce systematic effects, especially as greater distances are probed and the uncertainties become larger. In this paper, we combine several recent calibrations of the tip of the red giant branch (TRGB) method. These calibrations are internally self-consistent at the 1% level. New Gaia Early Data Release 3 data provide an additional consistency check at a (lower) 5% level of accuracy, a result of the well-documented Gaia angular covariance bias. The updated TRGB calibration applied to a sample of Type Ia supernovae from the Carnegie Supernova Project results in a value of the Hubble constant of H0 = 69.8 ± 0.6 (stat) ± 1.6 (sys) km s-1 Mpc-1. No statistically significant difference is found between the value of H0 based on the TRGB and that determined from the cosmic microwave background. The TRGB results are also consistent to within 2σ with the SHoES and Spitzer plus Hubble Space Telescope (HST) Key Project Cepheid calibrations. The TRGB results alone do not demand additional new physics beyond the standard (ΛCDM) cosmological model. They have the advantage of simplicity of the underlying physics (the core He flash) and small systematic uncertainties (from extinction, metallicity, and crowding). Finally, the strengths and weaknesses of both the TRGB and Cepheids are reviewed, and prospects for addressing the current discrepancy with future Gaia, HST, and James Webb Space Telescope observations are discussed. Resolving this discrepancy is essential for ascertaining if the claimed tension in H0 between the locally measured and CMB-inferred values is physically motivated. * Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program Nos. 13472, 13691, 9477, and 10399.

Keywords: cosmology; hubble constant; cepheid variable stars; red giant stars; stellar distance; observational cosmology
Age-dating Red Giant Stars Associated with Galactic Disk and Halo Substructures

The vast majority of Milky Way stellar halo stars were likely accreted from a small number (≲3) of relatively large dwarf galaxy accretion events. However, the timing of these events is poorly constrained and predominantly relies on indirect dynamical mixing arguments or imprecise age measurements of stars associated with debris structures. Here, we aim to infer robust stellar ages for stars associated with galactic substructures to more directly constrain the merger history of the Galaxy. By combining kinematic, asteroseismic, and spectroscopic data where available, we infer stellar ages for a sample of 10 red giant stars that were kinematically selected to be within the stellar halo, a subset of which are associated with the Gaia-Enceladus-Sausage halo substructure, and compare their ages to 3 red giant stars in the Galactic disk. Despite systematic differences in both absolute and relative ages determined here, age rankings of stars in this sample are robust. Passing the same observable inputs to multiple stellar age determination packages, we measure a weighted average age for the Gaia-Enceladus-Sausage stars in our sample of 8 ± 3 (stat.) ± 1 (sys.) Gyr. We also determine hierarchical ages using isochrones for the populations of Gaia-Enceladus-Sausage, in situ halo and disk stars, finding a Gaia-Enceladus-Sausage population age of 8.0 ${}_{-2.3}^{+3.2}$ Gyr. Although we cannot distinguish hierarchical population ages of halo or disk structures with our limited data and sample of stars, this framework should allow a distinct characterization of Galactic substructures using larger stellar samples and additional data available in the near future.

Keywords: asteroseismology; galactic archaeology; stellar kinematics; spectroscopy; hierarchical models
IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ~3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ~17° day-1. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.

Keywords: bl lacertae objects; spectropolarimetry; polarimetry; active galactic nuclei; jets; x-ray active galactic nuclei
Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). XVIII. The Dark Matter Halo Mass of Quasars at z 6

We present, for the first time, dark matter halo (DMH) mass measurement of quasars at z ~ 6 based on a clustering analysis of 107 quasars. Spectroscopically identified quasars are homogeneously extracted from the Hyper Suprime-Cam Strategic Survey Program wide layer over 891 deg2. We evaluate the clustering strength by three different autocorrelation functions: projected correlation function, angular correlation function, and redshift-space correlation function. The DMH mass of quasars at z ~ 6 is evaluated as ${5.0}_{-4.0}^{+7.4}\times {10}^{12}\,{h}^{-1}{M}_{\odot }$ with the bias parameter b = 20.8 ± 8.7 by the projected correlation function. The other two estimators agree with these values; though, each uncertainty is large. The DMH mass of quasars is found to be nearly constant ~1012.5 h -1 M ⊙ throughout cosmic time, suggesting that there is a characteristic DMH mass where quasars are always activated. As a result, quasars appear in the most massive halos at z ~ 6, but in less extreme halos thereafter. The DMH mass does not appear to exceed the upper limit of 1013 h -1 M ⊙, which suggests that most quasars reside in DMHs with ${M}_{\mathrm{halo}}\lt {10}^{13}{h}^{-1}{M}_{\odot }$ across most of the cosmic time. Our results supporting a significant increasing bias with redshift are consistent with the bias evolution model with inefficient active galactic nucleus feedback at z ~ 6. The duty cycle (f duty) is estimated as 0.019 ± 0.008 by assuming that DMHs in some mass interval can host a quasar. The average stellar mass is evaluated from stellar-to-halo mass ratio as ${M}_{* }={6.5}_{-5.2}^{+9.6}\times {10}^{10}\,{h}^{-1}{M}_{\odot }$ , which is found to be consistent with [C II] observational results.

Keywords: large-scale structure of the universe; quasars; supermassive black holes
Gravitational Redshift Detection from the Magnetic White Dwarf Harbored in RX J1712.6-2414

Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary system, RX J1712.6-2414, obtained from the Chandra High Energy Transmission Grating observation, we detected significant redshifts for characteristic X-rays emitted from hydrogen-like magnesium, silicon (ΔE/E rest ~ 7 × 10-4), and sulfur (ΔE/E rest ~ 15 × 10-4) ions, which are over the instrumental absolute energy accuracy (ΔE/E rest ~ 3.3 × 10-4). Considering some possible factors, such as Doppler shifts associated with the plasma flow, systemic velocity, and optical depth, we concluded that the major contributor to the observed redshift is the gravitational redshift of the WD harbored in the binary system, which is the first gravitational redshift detection from a magnetic WD. Moreover, the gravitational redshift provides us with a new method of WD mass measurement by invoking the plasma-flow theory with strong magnetic fields in close binaries. Regardless of large uncertainty, our new method estimated the WD mass to be M WD > 0.9 M ⊙.

Keywords: white dwarf stars; x-ray binary stars; x-ray point sources; cataclysmic variable stars; dq herculis stars; stellar accretion; magnetic fields; magnetic poles; plasma astrophysics; gravitational fields; redshifted