adsabs/SciX_UAT_keywords huggingface dataset:
Evidence for AGN-regulated Cooling in Clusters at z 1.4: A Multiwavelength View of SPT-CL J0607-4448

We present a multiwavelength analysis of the galaxy cluster SPT-CL J0607-4448 (SPT0607), which is one of the most distant clusters discovered by the South Pole Telescope at z = 1.4010 ± 0.0028. The high-redshift cluster shows clear signs of being relaxed with well-regulated feedback from the active galactic nucleus (AGN) in the brightest cluster galaxy (BCG). Using Chandra X-ray data, we construct thermodynamic profiles and determine the properties of the intracluster medium. The cool-core nature of the cluster is supported by a centrally peaked density profile and low central entropy ( ${K}_{0}={18}_{-9}^{+11}$ keV cm2), which we estimate assuming an isothermal temperature profile due to the limited spectral information given the distance to the cluster. Using the density profile and gas cooling time inferred from the X-ray data, we find a mass-cooling rate ${\dot{M}}_{\mathrm{cool}}={100}_{-60}^{+90}\,{M}_{\odot }$ yr-1. From optical spectroscopy and photometry around the [O II] emission line, we estimate that the BCG star formation rate is ${\mathrm{SFR}}_{[{\rm{O}}\,{\rm\small{II}}]}={1.7}_{-0.6}^{+1.0}\,{M}_{\odot }$ yr-1, roughly two orders of magnitude lower than the predicted mass-cooling rate. In addition, using ATCA radio data at 2.1 GHz, we measure a radio jet power ${P}_{\mathrm{cav}}={3.2}_{-1.3}^{+2.1}\times {10}^{44}$ erg s-1, which is consistent with the X-ray cooling luminosity ( ${L}_{\mathrm{cool}}={1.9}_{-0.5}^{+0.2}\times {10}^{44}$ erg s-1 within r cool = 43 kpc). These findings suggest that SPT0607 is a relaxed, cool-core cluster with AGN-regulated cooling at an epoch shortly after cluster formation, implying that the balance between cooling and feedback can be reached quickly. We discuss the implications for these findings on the evolution of AGN feedback in galaxy clusters.

Keywords: brightest cluster galaxies; galaxy clusters; intracluster medium; radio galaxies; high-redshift galaxy clusters
Forecasting Solar Cycle 25 with a Principled Bayesian Two-stage Statistical Model

We update the Bayesian analysis of sunspot numbers (SSNs) developed by Yu et al. prior to the peak of Solar Cycle 24 to account for the recalibration of the SSN index. We show that the model yields an accurate hindcast of Cycle 24 with the revised SSN, and use the data acquired since then to predict the strength and peak of Cycle 25. We predict the behavior of Cycle 25 to be moderate to weak, with a peak SSN of 120±27 to occur c. 2025 July (±7 months).

Keywords: solar cycle; sunspot number; hierarchical models
The Effects of Methane Clathrates on the Thermal and Seismic Profile of Titan's Icy Lithosphere

We investigate the effects of methane clathrates on Titan's thermal and seismic structure. The Dragonfly mission is planned to arrive at Titan in 2033 with a payload that includes a seismic package. The seismic instruments are tasked with recording seismic events and recovering the internal structure. Here, we explore whether differences in thermal and seismic profiles between a pure water ice shell and an ice shell with a clathrate lid could be detectable with seismic instrumentation. Due to their lower thermal conductivity, clathrates reduce the conductive lid thickness thus altering the thermal profile. The differences between seismic velocities of clathrates and pure water ice, coupled with changes in the thermal profile, indicate the clathrate lid will create lower seismic velocities, particularly for the upper 10 km of the surface ice shell. The differences in P and S velocity at the surface are 2.9% and 4.5%, respectively, and reach up to 8.4% (for both P and S) at a depth of 9.6 km. Due to changes in thermal profile, the seismic attenuation of the ice shell will change such that clathrates will suppress surface wave amplitudes relative to the pure water ice model. The clathrate lid will further create minor changes (≤2.0%) in the surface wave dispersion curves. Dragonfly, or other future seismic investigations, could provide evidence for or against the presence of a clathrate lid by constraining the thermal and seismic profile of Titan's ice shell, by measuring the relative amplitudes of the surface to body waves, or by constraining the surface wave dispersion with high accuracy and precision.

Keywords: titan; planetary structure; planetary interior; surface ices
CEERS Key Paper. V. Galaxies at 4 < z < 9 Are Bluer than They Appear-Characterizing Galaxy Stellar Populations from Rest-frame 1 μm Imaging

We present results from the Cosmic Evolution Early Release Survey on the stellar population parameters for 28 galaxies with redshifts 4 < z < 9 using imaging data from the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) combined with data from the Hubble Space Telescope and the Spitzer Space Telescope. The JWST/MIRI 5.6 and 7.7 μm data extend the coverage of the rest-frame spectral energy distribution to nearly 1 μm for galaxies in this redshift range. By modeling the galaxies' SEDs the MIRI data show that the galaxies have, on average, rest-frame UV (1600 Å)-I-band colors 0.4 mag bluer than derived when using photometry that lacks MIRI. Therefore, the galaxies have lower ratios of stellar mass to light. The MIRI data reduce the stellar masses by $\langle {\rm{\Delta }}\mathrm{log}{M}_{* }\rangle =0.25$ dex at 4 < z < 6 and 0.37 dex at 6 < z < 9. This also reduces the star formation rates (SFRs) by <ΔlogSFR> = 0.14 dex at 4 < z < 6 and 0.27 dex at 6 < z < 9. The MIRI data also improve constraints on the allowable stellar mass formed in early star formation. We model this using a star formation history that includes both a "burst" at z f = 100 and a slowly varying ("delayed-τ") model. The MIRI data reduce the allowable stellar mass by 0.6 dex at 4 < z < 6 and by ≈1 dex at 6 < z < 9. Applying these results globally, this reduces the cosmic stellar-mass density by an order of magnitude in the early Universe (z ≈ 9). Therefore, observations of rest-frame ≳1 μm are paramount for constraining the stellar-mass buildup in galaxies at very high redshifts.

Keywords: galaxy evolution; galaxy formation; cosmology; galaxy colors; galaxy properties; galaxy masses; spectral energy distribution
Blanco DECam Bulge Survey (BDBS). VII. Multiple Populations in Globular Clusters of the Galactic Bulge

We present photometric evidence for multiple stellar populations (MPs) in 14 globular clusters (GCs) toward the southern Galactic bulge. The photometric data come as part of the Blanco DECam Bulge Survey, which is a deep, wide-field near-UV-near-IR (ugrizY) survey of the southern Galactic bulge. Here, we present the first systematic study of bulge GC multiple populations with deep photometry including the u band, which is a crucial indicator of the abundance of CNO-bearing molecules in stellar atmospheres. We identify cluster members using Gaia EDR3 proper motion measurements, and then isolate red giant branch stars using r versus u - r color-magnitude diagrams. We find evidence suggesting all 14 clusters host at least two populations, and NGC 6441, NGC 6626, and NGC 6656 appear to have at least three populations. Many of these clusters are not part of the Hubble Space Telescope (HST) surveys nor do they have comprehensive spectroscopic analyses so we are presenting the first evidence of MPs in several clusters. Not only do we find a strong anticorrelation between the fraction of first-generation stars and cluster absolute V magnitude, but the correlation coefficient and cluster-to-cluster scatter are similar to the results obtained from HST. Our ground-based data extend to much larger radial distances than similar HST observations, enabling a reliable estimate of the global fraction of first-generation stars in each cluster. This study demonstrates that ground-based u-band photometry as provided by DECam will prove powerful in the study of multiple populations in resolved GCs.

Keywords: globular star clusters; red giant stars; broad band photometry; galactic bulge; ultraviolet astronomy
Revised Surface Abundances of R Coronae Borealis Stars

Surface abundances of 14 (11 majority class and three minority class) R Coronae Borealis stars (RCBs) along with the final-flash object, V4334 Sgr (Sakurai's object) are revised based on their carbon abundances measured from the observed C2 bands; note that the earlier reported abundances were derived using an assumed carbon abundance due to the well-known carbon problem. The hot RCB star MV Sgr is not subject to a carbon problem; it is remarkable to note that MV Sgr's carbon abundance lies in the range that is measured for the majority and minority class RCBs. The revised iron abundances for the RCBs are in the range $\mathrm{log}\epsilon $ (Fe) = 3.8 to $\mathrm{log}\epsilon $ (Fe) = 5.8 with the minority class RCB star V854 Cen at the lower end and the majority class RCB star R CrB at the higher end of this range. Indications are that the revised RCBs' metallicity range is roughly consistent with the metal-poor population contained within the bulge. The revised abundances of RCBs are then compared with extreme helium stars (EHes), the hotter relatives of RCBs. Clear differences are observed between RCBs and EHes in their metallicity distribution, carbon abundances, and the abundance trends observed for the key elements. These abundances are further discussed in light of their formation scenarios.

Keywords: chemical abundances; chemically peculiar stars; late stellar evolution
Inclination Excitation of Solar System Debris Disk Due to Stellar Flybys

Most stars form in clusters where relatively close encounters with other stars are common and can leave imprints on the orbital architecture of planetary systems. In this paper, we investigate the inclination excitation of debris disk particles due to such stellar encounters. We derive an analytical expression that describes inclination excitation in the hierarchical limit where the stellar flyby is distant. We then obtain numerical results for the corresponding particle inclination distribution in the nonhierarchical regime using a large ensemble of N-body simulations. For encounters with expected parameters, we find that the bulk inclination of the disk particles remains low. However, a distinct high-inclination population is produced by prograde stellar encounters for particles with final pericenter distances above 50 au. The maximum extent it of the inclination distribution scales with the inclination of the encounter $\sin ({i}_{s})$ for massive star flybys with low incoming velocity. The inclination distribution of observed trans-Neptunian objects places constraints on the dynamical history of our solar system. For example, these results imply an upper limit on product of the number density n of the solar birth cluster and the Sun's residence time τ of the form nτ ≲ 8 × 104 Myr pc-3. Stronger constraints can be derived with future observational surveys of the outer solar system.

Keywords: solar system; kuiper belt; solar system astronomy
Sensitivity of Polarization to Grain Shape. I. Convex Shapes

Aligned interstellar grains produce polarized extinction (observed at wavelengths from the far-ultraviolet to the mid-infrared) and polarized thermal emission (observed at far-infrared and submm wavelengths). The grains must be quite nonspherical, but the actual shapes are unknown. The relative efficacy for aligned grains to produce polarization at optical versus infrared wavelengths depends on particle shape. The discrete dipole approximation is used to calculate polarization cross sections for 20 different convex shapes, for wavelengths from 0.1 to 100 μm, and grain sizes a eff from 0.05 to 0.3 μm. Spheroids, cylinders, square prisms, and triaxial ellipsoids are considered. Minimum aspect ratios required by the observed starlight polarization are determined. Some shapes can also be ruled out because they provide too little or too much polarization at far-infrared and submm wavelengths. The ratio of 10 μm polarization to integrated optical polarization is almost independent of grain shape, varying by only ±8% among the viable convex shapes; thus, at least for convex grains, uncertainties in grain shape cannot account for the discrepancy between predicted and observed 10 μm polarization toward Cyg OB2-12.

Keywords: polarimetry; spectropolarimetry; dust physics; interstellar dust; radiative transfer
A New Stellar Mass Proxy for Subhalo Abundance Matching

Subhalo abundance matching (SHAM) has played an important role in improving our understanding of how galaxies populate their host dark matter halos. In essence, the SHAM framework is to find a dark matter halo property that best correlates with an attribute of galaxies, such as stellar mass. The peak value of the maximum circular velocity ( ${V}_{\max }$ ) a halo/subhalo has ever attained throughout its lifetime, V peak, has been a popular choice for SHAM. A recent study by Tonnesen & Ostriker suggested that quantity ϕ, which combines the present-day ${V}_{\max }$ and the peak value of halo dark matter mass, performs better in predicting stellar mass than V peak. Inspired by their approach, in this work, we find that further improvement can be achieved by a quantity ψ 5 that combines the 90th percentile of ${V}_{\max }$ a halo/subhalo has ever achieved with the 60th percentile of the dark matter halo time variation rate. Tests based on the simulation TNG300 of the IllustrisTNG project show that our new SHAM scheme, with just three free parameters, can improve the stellar mass prediction and mass-dependent clustering by 15% and 18% from ϕ, respectively, over the redshift range z = 0-2.

Keywords: galaxy formation; galaxy physics; galaxy dark matter halos
Luminosity Outburst Energized by the Collision between the Infalling Streamer and Disk in W51 North

We report the detection of the disk/torus, outflow, and inflow structures traced by H2O masers toward a high-mass young stellar object W51 North during its H2O maser outburst stage using the Karl G. Jansky Very Large Array (VLA). It is found that the disk has a radius of ~4000 au and an inclination angle with respect to the sky plane of ~60° by combining the VLA and the Atacama Large Millimeter/submillimeter Array data. Additionally, a peculiar flow perpendicular to the SiO bipolar outflow is detected in the H2O maser, SiO, and HC3N lines, which is newly-identified as an infalling streamer rather than an old outflow from this source, as reported in previous studies. Combining the VLA map and the Tianma radio telescope monitoring of the H2O masers suggests that the origin of the luminosity outburst of H2O masers during 2020 January-April is likely related to the energy release from the collision between the infalling streamer and the disk. This may provide an additional mechanism to account for the luminosity outburst or episodic accretion beyond disk fragmentation caused by gravitational instability.

Keywords: star formation; interstellar masers; astrophysical masers; young stellar objects; protostars; stellar accretion disks
The Evolution of the IR Luminosity Function and Dust-obscured Star Formation over the Past 13 Billion Years

We present the first results from the Mapping Obscuration to Reionization with ALMA (MORA) survey, the largest Atacama Large Millimeter/submillimeter Array (ALMA) blank-field contiguous survey to date (184 arcmin2) and the only at 2 mm to search for dusty star-forming galaxies (DSFGs). We use the 13 sources detected above 5σ to estimate the first ALMA galaxy number counts at this wavelength. These number counts are then combined with the state-of-the-art galaxy number counts at 1.2 and 3 mm and with a backward evolution model to place constraints on the evolution of the IR luminosity function and dust-obscured star formation in the past 13 billion years. Our results suggest a steep redshift evolution on the space density of DSFGs and confirm the flattening of the IR luminosity function at faint luminosities, with a slope of ${\alpha }_{\mathrm{LF}}=-{0.42}_{-0.04}^{+0.02}$ <!-- --> . We conclude that the dust-obscured component, which peaks at z ≈ 2-2.5, has dominated the cosmic history of star formation for the past ∼12 billion years, back to z ∼ 4. At z = 5, the dust-obscured star formation is estimated to be ∼35% of the total star formation rate density and decreases to 25%-20% at z = 6-7, implying a minor contribution of dust-enshrouded star formation in the first billion years of the universe. With the dust-obscured star formation history constrained up to the end of the epoch of reionization, our results provide a benchmark to test galaxy formation models, to study the galaxy mass assembly history, and to understand the dust and metal enrichment of the universe at early times.

Keywords: galaxy evolution; galaxies; dust continuum emission; millimeter astronomy; submillimeter astronomy; star formation; high-redshift galaxies; surveys; galaxy counts; luminosity function
Facilitating Interstellar Searches for Simple Amino Alcohols with Accurate Rest Frequencies into the Millimeter-wave Regime: Alaninol, Valinol, and Leucinol

The detection of larger complex organic molecules, such as molecules consisting of several functional groups or those which show conformational flexibility, in the interstellar medium could lead to insights into the availability of biomolecules in space. We present the rotational spectroscopic study of three amino alcohols: alaninol, valinol, and leucinol. The spectra were recorded over the 2-110 GHz region, which included the utilization of a newly developed instrument operating between 18-26 GHz. We report accurately determined line lists, rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling constants for two conformers of alaninol, four conformers of valinol, and three conformers of leucinol, as well as for several singly substituted heavy-atom isotopologues, which also provide structural insights. Further, a number of spectra of vibrationally excited states were assigned, and the associated motions were revealed with anharmonic frequency calculations. Accurate predictions of rotational transitions into the millimeter-wave regime for all species were made, facilitating searches for these complex molecules by observational facilities such as ALMA. Their detection would establish a new family of interstellar molecules.

Keywords: pre-biotic astrochemistry; high resolution spectroscopy; molecular spectroscopy; spectral line lists; interstellar medium; interstellar molecules
The Nature and Composition of Jupiter's Building Blocks Derived from the Water Abundance Measurements by the Juno Spacecraft

The microwave radiometer on board the Juno spacecraft provided a measurement of the water abundance found to range between ~1 and 5.1 times the protosolar abundance of oxygen in the near-equatorial region of Jupiter. Here, we aim to combine this up-to-date oxygen determination, which is likely to be more representative of the bulk abundance than the Galileo probe subsolar value, with the other known measurements of elemental abundances in Jupiter, to derive the formation conditions and initial composition of the building blocks agglomerated by the growing planet, and that determine the heavy element composition of its envelope. We investigate several cases of formation of icy solids in the protosolar nebula (PSN), from the condensation of pure ices to the crystallization of mixtures of pure condensates and clathrates in various proportions. Each of these cases corresponds to a distinct solid composition whose amount is adjusted in the envelope of Jupiter to match the O abundance measured by Juno. The volatile enrichments can be matched by a wide range of planetesimal compositions, from solids exclusively formed from pure condensates or from nearly exclusively clathrates, the latter case providing a slightly better fit. The total mass of volatiles needed in the envelope of Jupiter to match the observed enrichments is within the ~4.3-39 M⊕ range, depending on the crystallization scenario considered in the PSN. A wide range of masses of heavy elements derived from our fits is found to be compatible with the envelope's metallicity calculated from current interior models.

Keywords: jupiter; solar system gas giant planets; planet formation; solar system formation; planetesimals; protoplanetary disks
Tracing the Layers of Photodissociated Gas in the Trifid Nebula

Photodissociated gas bears the signature of the dynamical evolution of the ambient interstellar medium impacted by the mechanical and radiative feedback from an expanding H II region. Here we present an analysis of the kinematics of the young Trifid Nebula, based on velocity-resolved observations of the far-infrared fine structure lines of [C II] at 158 μm and [O I] at 63 μm. The distribution of the photodissociated regions (PDRs) surrounding the nebula is consistent with a shell-like structure created by the H II region expanding at a velocity of 5 km s‑1. Comparison of ratios of [C II] and [O I]63 μm intensities for identical velocity components with PDR models indicate a density of 104 cm‑3. The redshifted and blueshifted PDR shells with a combined mass of 516 M ⊙ have a kinetic energy of ∼1047 erg. This is consistent with the thermal energy of the H II region as well as with the energy deposited by the stellar wind luminosity from HD 169442A, an O7 V star, over the 0.5 Myr lifetime of the star. The observed momentum of the PDR shell is lower than what theoretical calculations predict for the radial momentum due to the shell being swept up by an expanding H II region, which suggests that significant mass loss has occurred in M20 due to the dispersal of the surrounding gas by the advancing ionization front.

Keywords: interstellar clouds; stellar-interstellar interactions; dense interstellar clouds; submillimeter astronomy
Semi-empirical Models of Spicule from Inversion of Ca II 8542 Å Line

We study a solar spicule observed off-limb using high-resolution imaging spectroscopy in the Ca II 8542 Å line obtained with the CRisp Imaging SpectroPolarimeter (CRISP) on the Swedish 1 m Solar Telescope. Using a new version of the non-LTE code NICOLE specifically developed for this problem we invert the spicule single- and double-peak line profiles. This new version considers off-limb geometry and computes atomic populations by solving the 1D radiative transfer assuming a vertical stratification. The inversion proceeds by fitting the observed spectral profiles at 14 different heights with synthetic profiles computed in the model by solving the radiative transfer problem along its length. Motivated by the appearance of double-peak Ca II 8542 Å spicule profiles, which exhibit two distinct emission features well separated in wavelength, we adopt a double-component scenario. We start from the ansatz that the spicule parameters are practically constant along the spicule axis for each component, except for a density drop. Our results support this ansatz by attaining very good fits to the entire set of 14 × 4 profiles (14 heights and 4 times). We show that the double-component model with uniform temperature of 9560 K, exponential decrease of density with a height scale of 1000-2000 km, and the counter-oriented line-of-sight velocities of components reproduce the double-peak line profiles at all spicule segments well. Analyses of the numerical response function reveals the necessity of the inversions of spectra at multiple height positions to obtain height-dependent, degeneracy-free reliable models with a limited number of free parameters.

Keywords: high resolution spectroscopy; radiative transfer; solar spicules; solar chromosphere; ground-based astronomy