adsabs/SciX_UAT_keywords huggingface dataset:
Gravothermal Solutions of SIDM Halos: Mapping from Constant to Velocity-dependent Cross Section

The scale-free gravothermal fluid formalism has long proved effective in describing the evolution of self-interacting dark matter halos with a constant dark matter particle cross section. However, whether the gravothermal fluid solutions match numerical simulations for velocity-dependent cross-section scenarios remains untested. In this work, we provide a fast mapping method that relates the constant-cross-section gravothermal solution to models with arbitrary velocity dependence in the cross section. We show that the gravothermal solutions after mapping are in good agreement with AREPO N-body simulation results. We illustrate the power of this approach by applying this fast mapping method to a halo hosting a low-surface-brightness galaxy, UGC 128. We show that this fast mapping method can be used to constrain free parameters in a physically motivated cross-section model and illustrate the parameter space favored by the rotation curve measurement.

Keywords: dark matter; milky way dark matter halo
Analytical Solution of Magnetically Dominated Astrophysical Jets and Winds: Jet Launching, Acceleration, and Collimation

We present an analytical solution of a highly magnetized jet/wind flow. The left side of the general force-free jet/wind equation (the "pulsar" equation) is separated into a rotating and a nonrotating term. The two equations with either term can be solved analytically, and the two solutions match each other very well. Therefore, we obtain a general approximate solution of a magnetically dominated jet/wind, which covers from the nonrelativistic to relativistic regimes, with the drift velocity well matching the cold plasma velocity. The acceleration of a jet includes three stages. (1) The jet flow is located within the Alfvén critical surface (i.e., the light cylinder), has a nonrelativistic speed, and is dominated by toroidal motion. (2) The jet is beyond the Alfvén critical surface where the flow is dominated by poloidal motion and becomes relativistic. The total velocity in these two stages follows the same law vΓ = ΩR. (3) The evolution law is replaced by $v{\rm{\Gamma }}\approx 1/\left(\theta \sqrt{2-\nu }\right)$ , where θ is the half-opening angle of the jet and 0 ≤ ν ≤ 2 is a free parameter determined by the magnetic field configuration. This is because the earlier efficient acceleration finally breaks the causality connection between different parts in the jet, preventing a global solution. The jet has to carry local charges and currents to support an electromagnetic balance. This approximate solution is consistent with known theoretical results and numerical simulations, and it is more convenient to directly compare with observations. This theory may be used to constrain the spin of black holes in astrophysical jets.

Keywords: relativistic jets; gamma-ray bursts; radio active galactic nuclei; active galactic nuclei; magnetic fields; astrophysical black holes; charged black holes; gamma-rays; cosmic rays; pulsars; neutron stars; high energy astrophysics
Long-period Jovian Tilts the Orbits of Two sub-Neptunes Relative to Stellar Spin Axis in Kepler-129

We present the discovery of Kepler-129 d ( ${P}_{d}={7.2}_{-0.3}^{+0.4}$ yr, $m\sin {i}_{d}={8.3}_{-0.7}^{+1.1}\,{M}_{\mathrm{Jup}}$ , ${e}_{d}={0.15}_{-0.05}^{+0.07}$ ) based on six years of radial-velocity observations from Keck/HIRES. Kepler-129 also hosts two transiting sub-Neptunes: Kepler-129 b (Pb = 15.79 days, rb = 2.40 ± 0.04 R⊕) and Kepler-129 c (Pc = 82.20 days, rc = 2.52 ± 0.07 R⊕) for which we measure masses of mb < 20 M⊕ and ${m}_{c}={43}_{-12}^{+13}\,{M}_{\oplus }$ . Kepler-129 is a hierarchical system consisting of two tightly packed inner planets and a massive external companion. In such a system, two inner planets precess around the orbital normal of the outer companion, causing their inclinations to oscillate with time. Based on an asteroseismic analysis of Kepler data, we find tentative evidence that Kepler-129 b and c are misaligned with stellar spin axis by ≳38°, which could be torqued by Kepler-129 d if it is inclined by ≳19° relative to inner planets. Using N-body simulations, we provide additional constraints on the mutual inclination between Kepler-129 d and inner planets by estimating the fraction of time during which two inner planets both transit. The probability that two planets both transit decreases as their misalignment with Kepler-129 d increases. We also find a more massive Kepler-129 c enables the two inner planets to become strongly coupled and more resistant to perturbations from Kepler-129 d. The unusually high mass of Kepler-129 c provides a valuable benchmark for both planetary dynamics and interior structure, since the best-fit mass is consistent with this 2.5 R⊕ planet having a rocky surface.

Keywords: radial velocity; asteroseismology; exoplanet dynamics
Cosmology with One Galaxy? The ASTRID Model and Robustness

Recent work has pointed out the potential existence of a tight relation between the cosmological parameter Ωm, at fixed Ωb, and the properties of individual galaxies in state-of-the-art cosmological hydrodynamic simulations. In this paper, we investigate whether such a relation also holds for galaxies from simulations run with a different code that makes use of a distinct subgrid physics: Astrid. We also find that in this case, neural networks are able to infer the value of Ωm with a ~10% precision from the properties of individual galaxies, while accounting for astrophysics uncertainties, as modeled in Cosmology and Astrophysics with MachinE Learning (CAMELS). This tight relationship is present at all considered redshifts, z ≤ 3, and the stellar mass, the stellar metallicity, and the maximum circular velocity are among the most important galaxy properties behind the relation. In order to use this method with real galaxies, one needs to quantify its robustness: the accuracy of the model when tested on galaxies generated by codes different from the one used for training. We quantify the robustness of the models by testing them on galaxies from four different codes: IllustrisTNG, SIMBA, Astrid, and Magneticum. We show that the models perform well on a large fraction of the galaxies, but fail dramatically on a small fraction of them. Removing these outliers significantly improves the accuracy of the models across simulation codes.

Keywords: cosmology
Photometric Redshift Estimation with Galaxy Morphology Using Self-organizing Maps

We use multiband optical and near-infrared photometric observations of galaxies in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey to predict photometric redshifts using artificial neural networks. The multiband observations span from 0.39 to 8.0 μm for a sample of ∼1000 galaxies in the GOODS-S field for which robust size measurements are available from Hubble Space Telescope Wide Field Camera 3 observations. We use self-organizing maps (SOMs) to map the multidimensional photometric and galaxy size observations while taking advantage of existing spectroscopic redshifts at 0 < z < 2 for independent training and testing sets. We show that use of photometric and morphological data led to redshift estimates comparable to redshift measurements from modeling of spectral energy distributions and from SOMs without morphological measurements.

Keywords: galaxy radii; galaxies; multi-color photometry; galaxy properties; redshifted
ForSE: A GAN-based Algorithm for Extending CMB Foreground Models to Subdegree Angular Scales

We present FORSE (Foreground Scale Extender), a novel Python package that aims to overcome the current limitations in the simulation of diffuse Galactic radiation, in the context of cosmic microwave background (CMB) experiments. FORSE exploits the ability of generative adversarial neural networks (GANs) to learn and reproduce complex features present in a set of images, with the goal of simulating realistic and non-Gaussian foreground radiation at subdegree angular scales. This is of great importance in order to estimate the foreground contamination to lensing reconstruction, delensing, and primordial B-modes for future CMB experiments. We applied this algorithm to Galactic thermal dust emission in both total intensity and polarization. Our results show how FORSE is able to generate small-scale features (at 12') having as input the large-scale ones (80'). The injected structures have statistical properties, evaluated by means of the Minkowski functionals, in good agreement with those of the real sky and which show the correct amplitude scaling as a function of the angular dimension. The obtained thermal dust Stokes Q and U full-sky maps as well as the FORSE package are publicly available for download.

Keywords: cosmic microwave background radiation; neural networks; diffuse radiation
Multiwavelength View of the M87 Black Hole Captured by the Event Horizon Telescope

In 2017, the first image of the center of the M87 galaxy was captured by the Event Horizon Telescope (EHT). It revealed a ring morphology and a size consistent with theoretical expectations for the light pattern around a weakly accreting supermassive black hole of ~6.5 billion solar masses. In parallel to the EHT measurements, an extensive multi-wavelength (MWL) campaign with ground- and space-based facilities from radio all the way up to the TeV energy range was organized. In this note we will give an overview of the results from this campaign. M87 was found to be in a historically low state. At X-ray energies the emission from the core dominates over HST-1. We present the most complete simultaneous, MWL spectrum of the active nucleus to date.

Keywords: astrophysical black holes; stellar mass black holes; black holes; radio galaxies; black hole physics; galaxies; jets; high energy astrophysics
Electron Signal Induced by GRB 221009A on Charged Particle Telescopes of POES and MetOp Satellites

GRB 221009A is a long gamma-ray burst among the most energetic and nearest (z = 0.151) detected so far. The energy fluence of the burst was so large to cause ionization of the upper layers of Earth's atmosphere and also observable signals in satellite-borne particle detectors. Electron signals, with the same GRB time development, can arise from the interaction of energetic photons with the particle detector and support structures. This effect was previously reported for the HEPP-L on board the China Seismo-Electromagnetic Satellite. We searched for the same effect on the particle detectors on board five POES and MetOp satellites. Electron signals in coincidence with the gamma-ray emission of the burst were found in three satellites, which were well illuminated by the GRB. The properties of the found electron signals are reported and discussed.

Keywords: gamma-ray bursts
RR Lyrae Variables in Messier 53: Near-infrared Period-Luminosity Relations and the Calibration Using Gaia Early Data Release 3

We present new near-infrared, JHKs, period-luminosity relations (PLRs) for RR Lyrae variables in the Messier 53 (M53 or NGC 5024) globular cluster. Multi-epoch JHKs observations, obtained with the WIRCam instrument on the 3.6 m Canada-France-Hawaii Telescope, are used for the first time to estimate precise mean magnitudes for 63 RR Lyrae stars in M53 including 29 fundamental-mode (RRab) and 34 first-overtone mode (RRc) variables. The JHKs-band PLRs for RR Lyrae stars are best constrained for RRab types with a minimal scatter of 22, 23, and 19 mmag, respectively. The combined sample of RR Lyrae is used to derive the Ks-band PLR, ${K}_{s}=-2.303(0.063)\mathrm{log}P+15.212(0.016)$ ,exhibiting a 1σ dispersion of only 0.027 mag. Theoretical period-luminosity-metallicity (PLZ) relations are used to predict parallaxes for 400 Galactic RR Lyrae, resulting in a median parallax zero-point offset of -7 ± 3 μas in Gaia Early Data Release 3 (EDR3), which increases to 22 ± 2 μas if the parallax corrections are applied. We also estimate a robust distance modulus, μM53 = 16.403 ± 0.024 (statistical) ± 0.033 (systematic) mag, to M53 based on theoretical calibrations. Homogeneous and precise mean magnitudes for RR Lyrae in M53 together with similar literature data for M3, M4, M5, and ω Cen are used to empirically calibrate a new RR Lyrae ${\mathrm{PLZ}}_{{K}_{s}}$ relation, ${K}_{s}=-0.848(0.007)\,-2.320(0.006)\mathrm{log}P+0.166(0.011)[\mathrm{Fe}/{\rm{H}}]$ ,anchored with Gaia EDR3 distances and theoretically predicted relations, and to simultaneously estimate precise RR Lyrae-based distances to these globular clusters.

Keywords: rr lyrae variable stars; stellar pulsations; globular star clusters; distance indicators; distance measure
A New Third Planet and the Dynamical Architecture of the HD 33142 Planetary System

Based on recently-taken and archival HARPS, FEROS, and HIRES radial velocities (RVs), we present evidence for a new planet orbiting the first ascent red giant star HD 33142 (with an improved mass estimate of M1.52 ± 0.03 M ⊙), already known to host two planets. We confirm the Jovian-mass planets HD 33142b and c, with periods of P b = ${330.0}_{-0.4}^{+0.4}$ days and P c = ${810.2}_{-4.2}^{+3.8}$ days and minimum dynamical masses of ${m}_{{\rm{b}}}\sin i$ = ${1.26}_{-0.05}^{+0.05}$ M Jup and ${m}_{{\rm{c}}}\sin i$ = ${0.89}_{-0.05}^{+0.06}$ MJup, respectively. Furthermore, our periodogram analysis of the precise RVs shows strong evidence for a short-period Doppler signal in the residuals of a two-planet Keplerian fit, which we interpret as a third, Saturn-mass planet with ${m}_{{\rm{d}}}\sin i$ = ${0.20}_{-0.03}^{+0.02}$ M Jup in a close-in orbit with an orbital period of P d = ${89.9}_{-0.1}^{+0.1}$ days. We study the dynamical behavior of the three-planet system configuration with an N-body integration scheme, finding it to be long-term stable with the planets alternating between low and moderate eccentricity episodes. We also perform N-body simulations, including stellar evolution and second-order dynamical effects such as planet-stellar tides and stellar mass loss on the way to the white dwarf phase. We find that planets HD 33142b, c, and d are likely to be engulfed near the tip of the red giant branch phase due to tidal migration. These results make the HD 33142 system an essential benchmark for planet population statistics of the multiple-planet systems found around evolved stars. *Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under ESO programs 60.A-9700, 60.A-9036, 097.C-0090, 0100.C-0414, 0101.C-0232, 0102.C-0338, and MPG programs 088.C-0892, 099.A-9009, 0100.A-9006.

Keywords: exoplanet detection methods; exoplanet dynamics
Study of Star Clusters in the M83 Galaxy with a Convolutional Neural Network

We present a study of evolutionary and structural parameters of star cluster candidates in the spiral galaxy M83. For this we use a convolutional neural network trained on mock clusters and capable of fast identification and localization of star clusters, as well as inference of their parameters from multiband images. We use this pipeline to detect 3380 cluster candidates in Hubble Space Telescope observations. The sample of cluster candidates shows an age gradient across the galaxy's spiral arms, which is in good agreement with predictions of the density wave theory and other studies. As measured from the dust lanes of the spiral arms, the younger population of cluster candidates peaks at the distance of ∼0.4 kpc while the older candidates are more dispersed, but shifted toward ≳0.7 kpc in the leading part of the spiral arms. We find high-extinction cluster candidates positioned in the trailing part of the spiral arms, close to the dust lanes. We also find a large number of dense older clusters near the center of the galaxy and a slight increase of the typical cluster size further from the center.

Keywords: star clusters; galaxies; convolutional neural networks
Tectonics and Seismicity of the Lunar South Polar Region

The lunar south pole regions are subjected to global stresses that result in contractional deformation and associated seismicity. This deformation is mainly expressed by lobate thrust fault scarps; examples are globally distributed, including polar regions. One small cluster of lobate scarps falls within the de Gerlache Rim 2 Artemis III candidate landing region. The formation of the largest de Gerlache scarp, less than 60 km from the pole, may have been the source of one of the strongest shallow moonquakes recorded by the Apollo Passive Seismic Network. The scarp is within a probabilistic space of relocated epicenters for this event determined in a previous study. Modeling suggests that a shallow moonquake with an M w of ∼5.3 may have formed the lobate thrust fault scarp. We modeled the peak ground acceleration generated by such an event and found that strong to moderate ground shaking is predicted at a distance from the source of at least ∼40 km, while moderate to light shaking may extend beyond ∼50 km. Models of the slope stability in the south polar region predict that most of the steep slopes in Shackleton crater are susceptible to regolith landslides. Light seismic shaking may be all that is necessary to trigger regolith landslides, particularly if the regolith has low cohesion (on the order of ∼0.1 kPa). The potential of strong seismic events from active thrust faults should be considered when preparing and locating permanent outposts and pose a possible hazard to future robotic and human exploration of the south polar region.

Keywords: lunar science; lunar features; lunar seismology
Laboratory and Astronomical Discovery of Magnesium Dicarbide, MgC2

We report the detection of magnesium dicarbide, MgC2, in the laboratory at centimeter wavelengths and assign 24MgC2, 25MgC2, and 26MgC2 to 14 unidentified lines in the radio spectrum of the circumstellar envelope of the evolved carbon star IRC+10216. The structure of MgC2 is found to be T-shaped with a highly ionic bond between the metal atom and the C2 unit, analogous to other dicarbides containing electropositive elements. A two-temperature excitation model of the MgC2 emission lines observed in IRC+10216 yields a very low rotational temperature of 6 ± 1 K, a kinetic temperature of 22 ± 13 K, and a column density of (1.0 ± 0.3) × 1012 cm-2. The abundance of MgC2 relative to the magnesium-carbon chains MgCCH, MgC4H, and MgC6H is 1:2:22:20 and provides a new constraint on the sequential radiative association-dissociative recombination mechanisms implicated in the production of metal-bearing molecules in circumstellar environments.

Keywords: circumstellar envelopes; metal-containing molecules; laboratory astrophysics; carbon stars
Identification and Quenching of Nugget Galaxies in the RESOLVE Survey at z = 0

We present a complete census of candidate nuggets, i.e., dense galaxies likely formed by compaction with intense gas influx, within the volume-limited redshift z ∼ 0 REsolved Spectroscopy Of a Local VolumE (RESOLVE) survey. These nuggets span all evolutionary stages and 3 orders of magnitude in stellar mass (M * ∼ 108 to 1011 M ⊙) from the dwarf to the giant regime. We develop selection criteria for our z ∼ 0 nugget candidates based on structure and introduce the use of environmental criteria to eliminate nugget-like objects with suspected non-compaction origins. The resulting z ∼ 0 nuggets follow expectations with respect to structure (i.e., density, size), population frequency, and likely origins. We show that the properties of our nugget census are consistent with permanent quenching above the gas-richness threshold scale (halo mass M halo ∼ 1011.4 M ⊙), cyclic temporary quenching below the threshold scale, and feedback from active galactic nuclei (AGN) assisting in permanent quenching. As predicted in simulations, most nuggets quench within a halo mass range of M halo ∼ 1011.45 to 1011.9 M ⊙. We find ∼0.29 dex scatter around the star-forming main sequence for candidate blue nuggets below the threshold scale, which is consistent with temporary quenching as seen in simulations. A transitional population of green nuggets appears above the threshold scale. AGN also become more common in nuggets above this scale, and we see a likely AGN excess in nuggets versus comparably selected non-nuggets. Our results provide the first observational confirmation of the mass-dependent, AGN-mediated shift from cyclic quenching to halo quenching in nuggets.

Keywords: galaxy bulges; galaxy evolution; galaxy quenching; blue compact dwarf galaxies; early-type galaxies; elliptical galaxies; galaxy formation; lenticular galaxies
Outgassing Composition of the Murchison Meteorite: Implications for Volatile Depletion of Planetesimals and Interior-atmosphere Connections for Terrestrial Exoplanets

Outgassing is a central process during the formation and evolution of terrestrial planets and their atmospheres both within and beyond the solar system. Although terrestrial planets' early atmospheres likely form via outgassing during planetary accretion, the connection between a planet's bulk composition and its initial atmospheric properties is not well understood. One way to inform this connection is to analyze the outgassing compositions of meteorites, and in particular carbonaceous chondrites, because they are some of the most volatile-rich, primitive materials (in terms of their bulk compositions) that are available for direct study. In addition, they may serve as compositional analogs for the building block materials of terrestrial planets in our solar system and around other Sun-like stars. This study builds upon previous outgassing experiments that monitored the abundances of volatile species (e.g., H2O, CO, and CO2) released from the Murchison meteorite. To gain a more complete understanding of Murchison's outgassing composition, we perform a series of heating experiments under atmospheric pressure (1 bar) and vacuum (~10-9 bar) conditions on samples of the Murchison meteorite and subsequent bulk element analysis to inform the outgassing trends of a suite of major elements in Murchison (e.g., Fe, Mg, Zn, and S). Under both pressure conditions, sulfur outgases significantly at the highest temperatures (~800°C-1000 °C). For the samples heated under vacuum conditions, we also detect outgassing of zinc. Combined with prior outgassing experiments, this study provides important insights into the volatile depletion patterns of undifferentiated planetesimals and the early outgassing compositions of terrestrial exoplanets.

Keywords: meteorite composition; planetary atmospheres; exoplanet atmospheric composition; planetesimals