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<jats:title>Abstract</jats:title> <jats:p>We measure the evolution of the <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> relation using 584 uniformly selected Sloan Digital Sky Survey quasars at 0.2 &lt; <jats:italic>z</jats:italic> &lt; 0.8. The black hole masses (<jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>) are derived from the single-epoch virial mass estimator using the H<jats:italic>β</jats:italic> emission line and span the range <jats:inline-formula> <jats:tex-math> <?CDATA $7.0\lt \mathrm{log}\,{{ \mathcal M }}_{\mathrm{BH}}/{M}_{\odot }\lt 9.5$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>7.0</mml:mn> <mml:mo>&lt;</mml:mo> <mml:mi>log</mml:mi> <mml:mspace width="0.25em" /> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo>&lt;</mml:mo> <mml:mn>9.5</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>. The host-galaxy stellar masses (<jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>), which cover the interval <jats:inline-formula> <jats:tex-math> <?CDATA $10.0\lt \mathrm{log}\,{{ \mathcal M }}_{\star }/{M}_{\odot }\lt 11.5$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>10.0</mml:mn> <mml:mo>&lt;</mml:mo> <mml:mi>log</mml:mi> <mml:mspace width="0.25em" /> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo>&lt;</mml:mo> <mml:mn>11.5</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn5.gif" xlink:type="simple" /> </jats:inline-formula>, are determined by performing two-dimensional quasar-host decomposition of the Hyper Suprime-Cam images and spectral energy distribution fitting. To quantify sample selection biases and measurement uncertainties on the mass terms, a mock quasar sample is constructed to jointly constrain the redshift evolution of the <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> relation and its intrinsic scatter (<jats:italic>σ</jats:italic> <jats:sub> <jats:italic>μ</jats:italic> </jats:sub>) through forward modeling. We find that the level of evolution is degenerate with <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>μ</jats:italic> </jats:sub>, such that both a positive mild evolution (i.e., <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}/{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn7.gif" xlink:type="simple" /> </jats:inline-formula> increases with redshift) with a small <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>μ</jats:italic> </jats:sub> and a negative mild evolution with a larger <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>μ</jats:italic> </jats:sub> are consistent with our data. The posterior distribution of <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>μ</jats:italic> </jats:sub> enables us to put a strong constraint on the intrinsic scatter of the <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn8.gif" xlink:type="simple" /> </jats:inline-formula> relation, which has a best inference of <jats:inline-formula> <jats:tex-math> <?CDATA ${0.25}_{-0.04}^{+0.03}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.25</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.04</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.03</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn9.gif" xlink:type="simple" /> </jats:inline-formula> dex, consistent with the local value. The redshift evolution of the <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn10.gif" xlink:type="simple" /> </jats:inline-formula> relation relative to the local relation is constrained to be <jats:inline-formula> <jats:tex-math> <?CDATA ${\left(1+z\right)}^{{0.12}_{-0.27}^{+0.28}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo> <mml:mi>z</mml:mi> </mml:mrow> </mml:mfenced> </mml:mrow> <mml:mrow> <mml:msubsup> <mml:mrow> <mml:mn>0.12</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.27</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.28</mml:mn> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn11.gif" xlink:type="simple" /> </jats:inline-formula>, in agreement with no significant evolution since <jats:italic>z</jats:italic> ∼ 0.8. The tight and unevolving <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn12.gif" xlink:type="simple" /> </jats:inline-formula> relation is suggestive of a coupling through active galactic nuclei feedback or/and a common gas supply at work, thus restricting the mass ratio of galaxies and their black holes to a limited range. Given the considerable stellar disk component, the <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\mathrm{bulge}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>–</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi>bulge</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac2301ieqn13.gif" xlink:type="simple" /> </jats:inline-formula> relation may evolve as previously seen at higher redshifts.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We apply a friends-of-friends (FoF) algorithm to identify galaxy clusters and we use the catalog to explore the evolutionary synergy between brightest cluster galaxies (BCGs) and their host clusters. We base the cluster catalog on the dense HectoMAP redshift survey (2000 redshifts deg<jats:sup>−2</jats:sup>). The HectoMAP FoF catalog includes 346 clusters with 10 or more spectroscopic members within the range 0.05 &lt; <jats:italic>z</jats:italic> &lt; 0.55 and with a median <jats:italic>z</jats:italic> = 0.29. We list these clusters and their members. We also include central velocity dispersions (<jats:italic>σ</jats:italic> <jats:sub>*,BCG</jats:sub>) for the FoF cluster BCGs, a distinctive feature of the HectoMAP FoF catalog. HectoMAP clusters with higher galaxy number density (80 systems) are all genuine clusters with a strong concentration and a prominent BCG in Subaru/Hyper Suprime-Cam images. The phase-space diagrams show the expected elongation along the line of sight. Lower-density systems include some low reliability systems. We establish a connection between BCGs and their host clusters by demonstrating that <jats:italic>σ</jats:italic> <jats:sub>*,<jats:italic>BCG</jats:italic> </jats:sub>/<jats:italic>σ</jats:italic> <jats:sub>cl</jats:sub> decreases as a function of cluster velocity dispersion (<jats:italic>σ</jats:italic> <jats:sub>cl</jats:sub>), in contrast, numerical simulations predict a constant <jats:italic>σ</jats:italic> <jats:sub>*,BCG</jats:sub>/<jats:italic>σ</jats:italic> <jats:sub>cl</jats:sub>. Sets of clusters at two different redshifts show that BCG evolution in massive systems is slow over the redshift range <jats:italic>z</jats:italic> &lt; 0.4. The data strongly suggest that minor mergers may play an important role in BCG evolution in clusters with <jats:italic>σ</jats:italic> <jats:sub>cl</jats:sub> ≳ 300 km s<jats:sup>−1</jats:sup>. For lower mass systems (<jats:italic>σ</jats:italic> <jats:sub>cl</jats:sub> &lt; 300 km s<jats:sup>−1</jats:sup>), major mergers may play a significant role. The coordinated evolution of BCGs and their host clusters provides an interesting test of simulations in high-density regions of the universe.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a follow-up analysis examining the dynamics and structures of 41 massive, large star-forming galaxies at <jats:italic>z</jats:italic> ∼ 0.67 − 2.45 using both ionized and molecular gas kinematics. We fit the galaxy dynamics with models consisting of a bulge, a thick, turbulent disk, and an NFW dark matter halo, using code that fully forward-models the kinematics, including all observational and instrumental effects. We explore the parameter space using Markov Chain Monte Carlo (MCMC) sampling, including priors based on stellar and gas masses and disk sizes. We fit the full sample using extracted 1D kinematic profiles. For a subset of 14 well-resolved galaxies, we also fit the 2D kinematics. The MCMC approach robustly confirms the results from least-squares fitting presented in Paper I: the sample galaxies tend to be baryon-rich on galactic scales (within one effective radius). The 1D and 2D MCMC results are also in good agreement for the subset, demonstrating that much of the galaxy dynamical information is captured along the major axis. The 2D kinematics are more affected by the presence of noncircular motions, which we illustrate by constructing a toy model with constant inflow for one galaxy that exhibits residual signatures consistent with radial motions. This analysis, together with results from Paper I and other studies, strengthens the finding that massive, star-forming galaxies at <jats:italic>z</jats:italic> ∼ 1 − 2 are baryon-dominated on galactic scales, with lower dark matter fractions toward higher baryonic surface densities. Finally, we present details of the kinematic fitting code used in this analysis.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Exoplanets with radii between those of Earth and Neptune have stronger surface gravity than Earth, and can retain a sizable hydrogen-dominated atmosphere. In contrast to gas giant planets, we call these planets gas dwarf planets. The James Webb Space Telescope (JWST) will offer unprecedented insight into these planets. Here, we investigate the detectability of ammonia (NH<jats:sub>3</jats:sub>, a potential biosignature) in the atmospheres of seven temperate gas dwarf planets using various JWST instruments. We use <jats:monospace>petitRadTRANS</jats:monospace> and <jats:monospace>PandExo</jats:monospace> to model planet atmospheres and simulate JWST observations under different scenarios by varying cloud conditions, mean molecular weights (MMWs), and NH<jats:sub>3</jats:sub> mixing ratios. A metric is defined to quantify detection significance and provide a ranked list for JWST observations in search of biosignatures in gas dwarf planets. It is very challenging to search for the 10.3–10.8 <jats:italic>μ</jats:italic>m NH<jats:sub>3</jats:sub> feature using eclipse spectroscopy with the Mid-Infrared Instrument (MIRI) in the presence of photon and a systemic noise floor of 12.6 ppm for 10 eclipses. NIRISS, NIRSpec, and MIRI are feasible for transmission spectroscopy to detect NH<jats:sub>3</jats:sub> features from 1.5–6.1 <jats:italic>μ</jats:italic>m under optimal conditions such as a clear atmosphere and low MMWs for a number of gas dwarf planets. We provide examples of retrieval analyses to further support the detection metric that we use. Our study shows that searching for potential biosignatures such as NH<jats:sub>3</jats:sub> is feasible with a reasonable investment of JWST time for gas dwarf planets given optimal atmospheric conditions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The study of infall motion helps us to understand the initial stages of star formation. In this paper, we use the IRAM 30 m telescope to make mapping observations of 24 infall sources confirmed in previous work. The lines we use to track gas infall motions are HCO<jats:sup>+</jats:sup> (1-0) and H<jats:sup>13</jats:sup>CO<jats:sup>+</jats:sup> (1-0). All 24 sources show HCO<jats:sup>+</jats:sup> emissions, while 18 sources show H<jats:sup>13</jats:sup>CO<jats:sup>+</jats:sup> emissions. The HCO<jats:sup>+</jats:sup> integrated intensity maps of 17 sources show clear clumpy structures; for the H<jats:sup>13</jats:sup>CO<jats:sup>+</jats:sup> line, 15 sources show clumpy structures. We estimated the column density of HCO<jats:sup>+</jats:sup> and H<jats:sup>13</jats:sup>CO<jats:sup>+</jats:sup> using the RADEX radiation transfer code, and the obtained [HCO<jats:sup>+</jats:sup>]/[H<jats:sub>2</jats:sub>] and [H<jats:sup>13</jats:sup>CO<jats:sup>+</jats:sup>]/[HCO<jats:sup>+</jats:sup>] of these sources are about 10<jats:sup>−11</jats:sup>–10<jats:sup>−7</jats:sup> and 10<jats:sup>−3</jats:sup>–1, respectively. Based on the asymmetry of the line profile of the HCO<jats:sup>+</jats:sup>, we distinguish these sources: 19 sources show blue asymmetric profiles, and the other sources show red profiles or symmetric peak profiles. For eight sources that have double-peaked blue line profiles and signal-to-noise ratios greater than 10, the RATRAN model is used to fit their HCO<jats:sup>+</jats:sup> (1-0) lines, and to estimate their infall parameters. The mean <jats:italic>V</jats:italic> <jats:sub>in</jats:sub> of these sources is 0.3–1.3 km s<jats:sup>−1</jats:sup>, and the <jats:inline-formula> <jats:tex-math> <?CDATA ${\dot{M}}_{\mathrm{in}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>in</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac22abieqn1.gif" xlink:type="simple" /> </jats:inline-formula> is about 10<jats:sup>−3</jats:sup>–10<jats:sup>−4</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>, which is consistent with the results of intermediate or massive star formation in previous studies. The <jats:italic>V</jats:italic> <jats:sub>in</jats:sub> estimated from the Myers model is 0.1–1.6 km s<jats:sup>−1</jats:sup>, and the <jats:inline-formula> <jats:tex-math> <?CDATA ${\dot{M}}_{\mathrm{in}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>in</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac22abieqn2.gif" xlink:type="simple" /> </jats:inline-formula> is within 10<jats:sup>−3</jats:sup>–10<jats:sup>−5</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>. In addition, some identified infall sources show other star-forming activities, such as outflows and maser emissions. Especially for those sources with a double-peaked blue asymmetric profile, most of them have both infall and outflow evidence.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Red clump stars (RCs) are useful tracers of distances, extinction, chemical abundances, and Galactic structures and kinematics. Accurate estimation of RC parameters—absolute magnitude and intrinsic color—is the basis for obtaining high-precision RC distances. By combining astrometric data from Gaia; spectroscopic data from APOGEE and LAMOST; and multiband photometric data from Gaia, APASS, Pan-STARRS1, 2MASS, and WISE surveys, we use a Gaussian process regression to train machine learners to derive the multiband absolute magnitudes <jats:italic>M</jats:italic> <jats:sub> <jats:italic>λ</jats:italic> </jats:sub> and intrinsic colors <jats:inline-formula> <jats:tex-math> <?CDATA ${({\lambda }_{1}-{\lambda }_{2})}_{0}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo>−</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac22a7ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> for each spectral RC. The dependence of <jats:italic>M</jats:italic> <jats:sub> <jats:italic>λ</jats:italic> </jats:sub> on metallicity decreases from optical to infrared bands, while the dependence of <jats:italic>M</jats:italic> <jats:sub> <jats:italic>λ</jats:italic> </jats:sub> on age is relatively similar in each band. <jats:inline-formula> <jats:tex-math> <?CDATA ${({\lambda }_{1}-{\lambda }_{2})}_{0}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo>−</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac22a7ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> are more affected by metallicity than age. The RC parameters are not suitable to be represented by simple constants but are related to the Galactic stellar population structure. By analyzing the variation of <jats:italic>M</jats:italic> <jats:sub> <jats:italic>λ</jats:italic> </jats:sub> and <jats:inline-formula> <jats:tex-math> <?CDATA ${({\lambda }_{1}-{\lambda }_{2})}_{0}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo>−</mml:mo> <mml:msub> <mml:mrow> <mml:mi>λ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac22a7ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> in the spatial distribution, we construct (<jats:italic>R</jats:italic>, <jats:italic>z</jats:italic>) dependent maps of mean absolute magnitudes and mean intrinsic colors of the Galactic RCs. Through external and internal validation, we find that using three-dimensional (3D) parameter maps to determine RC parameters avoids systematic bias and reduces dispersion by about 20% compared to using constant parameters. Based on Gaia's EDR3 parallax, our 3D parameter maps, and extinction–distance profile selection, we obtain a photometric RC sample containing 11 million stars with distance and extinction measurements.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recent observations have revealed a population of <jats:italic>α</jats:italic>-element abundances, enhanced giant stars with unexpected high masses (≳1 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) from asteroseismic analysis and spectroscopy. Assuming single-star evolution, their masses imply young ages (<jats:italic>τ</jats:italic> &lt; 6 Gyr) incompatible with the canonical Galactic chemical evolution scenario. Here we study the chemistry and kinematics of a large sample of such <jats:italic>α</jats:italic>-rich, high-mass red giant branch (RGB) stars drawn from the LAMOST spectroscopic surveys. Using LAMOST and Gaia, we found these stars share the same kinematics as the canonical high-<jats:italic>α</jats:italic> old stellar population in the Galactic thick disk. The stellar abundances show that these high-<jats:italic>α</jats:italic> massive stars have <jats:italic>α</jats:italic>- and iron-peak element abundances similar to those of the high-<jats:italic>α</jats:italic> old thick-disk stars. However, a portion of them exhibit higher [(N+C)/Fe] and [Ba/Fe] ratios, which implies they have gained C- and Ba-rich materials from extra sources, presumably asymptotic giant branch (AGB) companions. The results support the previous suggestion that these RGB stars are products of binary evolution. Their high masses thus mimic “young” single stars, yet in fact they belong to an intrinsic old stellar population. To fully explain the stellar abundance patterns of our sample stars, a variety of binary evolution channels, such as main-sequence (MS) + RGB, MS + AGB, RGB + RGB, and RGB + AGB, are required, pointing to diverse formation mechanisms of these seemly rejuvenated cannibals. With this larger sample, our results confirm earlier findings that most, if not all, <jats:italic>α</jats:italic>-rich stars in the Galactic disk seem to be old.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Galaxies can grow through their mutual gravitational attraction and subsequent union. While orbiting a regular high-surface-brightness galaxy, the body of a low-mass galaxy can be stripped away. However, the stellar heart of the infalling galaxy, if represented by a tightly bound nuclear star cluster, is more resilient. From archival Hubble Space Telescope images, we have discovered a red, tidally stretched star cluster positioned ∼5″ (∼400 pc in projection) from, and pointing toward the center of, the post-merger spiral galaxy NGC 4424. The star cluster, which we refer to as “Nikhuli,” has a near-infrared luminosity of (6.88 ± 1.85) × 10<jats:sup>6</jats:sup> <jats:italic>L</jats:italic> <jats:sub>⊙,<jats:italic>F</jats:italic>160<jats:italic>W</jats:italic> </jats:sub> and likely represents the nucleus of a captured/wedded galaxy. Moreover, from our Chandra X-ray Observatory image, Nikhuli is seen to contain a high-energy X-ray point source, with <jats:inline-formula> <jats:tex-math> <?CDATA ${L}_{0.5-8\,\mathrm{keV}}={6.31}_{-3.77}^{+7.50}\times {10}^{38}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>L</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0.5</mml:mn> <mml:mo>−</mml:mo> <mml:mn>8</mml:mn> <mml:mspace width="0.25em" /> <mml:mi>keV</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>6.31</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.77</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>7.50</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>38</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac235bieqn1.gif" xlink:type="simple" /> </jats:inline-formula> erg s<jats:sup>−1</jats:sup> (90% confidence). We argue that this is more likely to be an active massive black hole than an X-ray binary. Lacking an outward-pointing comet-like appearance, the stellar structure of Nikhuli favors infall rather than the ejection from a gravitational-wave recoil event. A minor merger with a low-mass early-type galaxy may have sown a massive black hole, aided an X-shaped pseudobulge, and be sewing a small bulge. The stellar mass and the velocity dispersion of NGC 4424 predict a central black hole of (0.6–1.0) × 10<jats:sup>5</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>, similar to the expected intermediate-mass black hole in Nikhuli, and suggestive of a black hole supply mechanism for bulgeless late-type galaxies. We may potentially be witnessing black hole seeding by capture and sinking, with a nuclear star cluster the delivery vehicle.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Carbonyl sulfide (OCS) is an abundant sulfur (S)-bearing species in the interstellar medium. It is present not only in the gas phase, but also on interstellar grains as a solid; therefore, OCS very likely undergoes physicochemical processes on icy surfaces at very low temperatures. The present study experimentally and computationally investigates the reaction of solid OCS with hydrogen (H) atoms on amorphous solid water at low temperatures. The results show that the addition of H to OCS proceeds via quantum tunneling, and further addition of H leads to the formation of carbon monoxide (CO), hydrogen sulfide (H<jats:sub>2</jats:sub>S), formaldehyde (H<jats:sub>2</jats:sub>CO), methanol (CH<jats:sub>3</jats:sub>OH), and thioformic acid (HC(O)SH). These experimental results are explained by our quantum chemical calculations, which demonstrate that the initial addition of H to the S atom of OCS is the most predominant, leading to the formation of OCS-H radicals. Once the formed OCS-H radical is stabilized on ice, further addition of H to the S atom yields CO and H<jats:sub>2</jats:sub>S, while that to the C atom yields HC(O)SH. We have also confirmed, in a separate experiment, the HC(O)SH formation by the HCO reactions with the SH radicals. The present results would have an important implication for the recent detection of HC(O)SH toward G+0.693–0.027.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>With a mass of ∼1000 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> and a surface density of ∼0.5 g cm<jats:sup>−2</jats:sup>, G023.477+0.114, also known as IRDC 18310-4, is an infrared dark cloud (IRDC) that has the potential to form high-mass stars and has been recognized as a promising prestellar clump candidate. To characterize the early stages of high-mass star formation, we have observed G023.477+0.114 as part of the Atacama Large Millimeter/submillimeter Array (ALMA) Survey of 70 <jats:italic>μ</jats:italic>m Dark High-mass Clumps in Early Stages. We have conducted ∼1.″2 resolution observations with ALMA at 1.3 mm in dust continuum and molecular line emission. We have identified 11 cores, whose masses range from 1.1 to 19.0 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>. Ignoring magnetic fields, the virial parameters of the cores are below unity, implying that the cores are gravitationally bound. However, when magnetic fields are included, the prestellar cores are close to virial equilibrium, while the protostellar cores remain sub-virialized. Star formation activity has already started in this clump. Four collimated outflows are detected in CO and SiO. H<jats:sub>2</jats:sub>CO and CH<jats:sub>3</jats:sub>OH emission coincide with the high-velocity components seen in the CO and SiO emission. The outflows are randomly oriented for the natal filament and the magnetic field. The position-velocity diagrams suggest that episodic mass ejection has already begun even in this very early phase of protostellar formation. The masses of the identified cores are comparable to the expected maximum stellar mass that this IRDC could form (8–19 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>). We explore two possibilities on how IRDC G023.477+0.114 could eventually form high-mass stars in the context of theoretical scenarios.</jats:p>