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<jats:title>Abstract</jats:title> <jats:p>This work presents the medium-resolution (<jats:italic>R</jats:italic> ∼ 1500) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrowband photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (<jats:italic>T</jats:italic> <jats:sub>eff</jats:sub>, <jats:inline-formula> <jats:tex-math> <?CDATA $\mathrm{log}\,g$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mspace width="0.25em" /> <mml:mi>g</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7ab0ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, and [Fe/H]), as well as carbon and <jats:italic>α</jats:italic>-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that <jats:inline-formula> <jats:tex-math> <?CDATA ${92}_{-3}^{+2} \% $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>92</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>%</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7ab0ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> of the observed stars have [Fe/H] ≤ −1.0, <jats:inline-formula> <jats:tex-math> <?CDATA ${83}_{-3}^{+3} \% $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>83</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>%</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7ab0ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> have [Fe/H] ≤ −2.0, and <jats:inline-formula> <jats:tex-math> <?CDATA ${15}_{-3}^{+3} \% $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>15</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>%</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7ab0ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> have [Fe/H] ≤ −3.0, including two ultra metal-poor stars ([Fe/H] ≤ −4.0). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H] = −2.04. The sample also includes 68 carbon-enhanced metal-poor stars. Based on the calculated metallicities, further S-PLUS color cuts are proposed, which can increase the fractions of stars with [Fe/H] ≤ −1.0 and ≤ −2.0 to 98% and 88%, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Feedback from supernovae (SNe) is an essential mechanism that self-regulates the growth of galaxies, and a better model of SN feedback is still needed in galaxy-formation simulations. In the first part of this paper, using an Eulerian hydrodynamic code <jats:sc>Athena++</jats:sc>, we find the universal scaling relations for the time evolution of momentum and radius for a superbubble, when the momentum and time are scaled by those at the shell-formation time. In the second part of this paper, we develop a SN feedback model based on the <jats:sc>Athena++</jats:sc> simulation results utilizing Voronoi tessellation around each star particle, and implement it into the <jats:sc>GADGET3-Osaka</jats:sc> smoothed particle hydrodynamic code. Our feedback model was demonstrated to be isotropic and conservative in terms of energy and momentum. We examined the mass/energy/metal loading factors and find that our stochastic thermal feedback model produced galactic outflow that carries metals high above the galactic plane but with weak suppression of star formation. Additional mechanical feedback further suppressed star formation and brought the simulation results into better agreement with the observations of the Kennicutt–Schmidt relation, with all the results being within the uncertainties of observed data. We argue that both thermal and mechanical feedback are necessary for the SN feedback model of galaxy evolution when an individual SN bubble is unresolved.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The O’Connell effect—the presence of unequal maxima in eclipsing binaries—remains an unsolved riddle in the study of close binary systems. The Kepler space telescope produced high-precision photometry of nearly 3000 eclipsing binary systems, providing a unique opportunity to study the O’Connell effect in a large sample and in greater detail than in previous studies. We have characterized the observational properties—including temperature, luminosity, and eclipse depth—of a set of 212 systems (7.3% of Kepler eclipsing binaries) that display a maxima flux difference of at least 1%, representing the largest sample of O’Connell effect systems yet studied. We explored how these characteristics correlate with each other to help understand the O’Connell effect’s underlying causes. We also describe some system classes with peculiar light-curve features aside from the O’Connell effect (∼24% of our sample), including temporal variation and asymmetric minima. We found that the O’Connell effect size’s correlations with period and temperature are inconsistent with Kouzuma's starspot study. Up to 20% of systems display the parabolic eclipse timing variation signal expected for binaries undergoing mass transfer. Most systems displaying the O’Connell effect have the brighter maximum following the primary eclipse, suggesting a fundamental link between which maximum is brighter and the O’Connell effect’s physical causes. Most importantly, we find that the O’Connell effect occurs exclusively in systems where the components are close enough to significantly affect each other, suggesting that the interaction between the components is ultimately responsible for causing the O’Connell effect.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We describe the algorithm, implementation, and numerical tests of a multifluid dust module in the Athena++ magnetohydrodynamic code. The module can accommodate an arbitrary number of dust species interacting with the gas via aerodynamic drag (characterized by the stopping time), with a number of numerical solvers. In particular, we describe two second-order accurate, two-stage, fully implicit solvers that are stable in stiff regimes, including short stopping times and high dust mass loading, and they are paired with the second-order explicit van Leer and Runge–Kutta gas dynamics solvers in Athena++, respectively. Moreover, we formulate a consistent treatment of dust concentration diffusion with dust back-reaction, which incorporates momentum diffusion and ensures Galilean invariance. The new formulation and stiff drag solvers are implemented to be compatible with most of the existing features of Athena++, including different coordinate systems, mesh refinement, and shearing box and orbital advection. We present a large suite of test problems, including the streaming instability in linear and nonlinear regimes, as well as local and global settings, which demonstrate that the code achieves the desired performance. This module will be particularly useful for studies of dust dynamics and planet formation in protoplanetary disks.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Contact binary star systems represent the long-lived penultimate phase of binary evolution. Population statistics of their physical parameters inform an understanding of binary evolutionary pathways and end products. We use light curves and new optical spectroscopy to conduct a pilot study of ten (near) contact systems in the long-period (<jats:italic>P</jats:italic> &gt; 0.5 days) tail of close binaries in the Kepler field. We use PHOEBE light-curve models to compute Bayesian probabilities on five principal system parameters. Mass ratios and third-light contributions measured from spectra agree well with those inferred from the light curves. Pilot study systems have extreme mass ratios <jats:italic>q</jats:italic> &lt; 0.32. Most are triples. Analysis of the unbiased sample of 783 0.15 d &lt; <jats:italic>P</jats:italic> &lt; 2 days (near) contact binaries results in 178 probable contact systems, 114 probable detached systems, and 491 ambiguous systems for which we report best-fitting and 16th-/50th-/84th-percentile parameters. Contact systems are rare at periods <jats:italic>P</jats:italic> &gt; 0.5 days, as are systems with <jats:italic>q</jats:italic> &gt; 0.8. There exists an empirical mass ratio lower limit <jats:inline-formula> <jats:tex-math> <?CDATA ${q}_{\min }(P)$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>q</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>min</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>P</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac75bdieqn1.gif" xlink:type="simple" /> </jats:inline-formula> ≈ 0.05–0.15 below which contact systems are absent, supporting a new set of theoretical predictions obtained by modeling the evolution of contact systems under the constraints of mass and angular momentum conservation. Premerger systems should lie at long periods and near this mass ratio lower limit, which rises from <jats:italic>q</jats:italic> = 0.044 for <jats:italic>P</jats:italic> = 0.74 days to <jats:italic>q</jats:italic> = 0.15 at <jats:italic>P</jats:italic> = 2.0 days. These findings support a scenario whereby nuclear evolution of the primary (more massive) star drives mass transfer to the primary, thus moving systems toward extreme <jats:italic>q</jats:italic> and larger <jats:italic>P</jats:italic> until the onset of the Darwin instability at <jats:inline-formula> <jats:tex-math> <?CDATA ${q}_{\min }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>q</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>min</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac75bdieqn2.gif" xlink:type="simple" /> </jats:inline-formula> precipitates a merger.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The interstellar medium contains dust and gas, in which molecules can proliferate at high densities and in cold conditions. Interstellar complex organic molecules (iCOMs) are C-bearing species that contain at least six atoms. As they are detected in young stellar objects, iCOMs are expected to inhabit early stages of star formation evolution. In this study, we try to determine which iCOMs are present in the outflow component of massive protostars. To do this, we analyzed the morphological extension of blue- and redshifted iCOM emission in a sample of 11 massive protostars employing mapping observations at 1 mm within a ∼1 GHz bandwidth for both the IRAM-30 m and APEX telescopes. We modeled the iCOM emission of the central pointing spectra of our objects using the XCLASS local thermal equilibrium radiative transfer code. We detected the presence of several iCOMs such as CH<jats:sub>3</jats:sub>OH, <jats:sup>13</jats:sup>CH<jats:sub>3</jats:sub>OH, CH<jats:sub>3</jats:sub>OCHO, C<jats:sub>2</jats:sub>H<jats:sub>5</jats:sub>C<jats:sup>15</jats:sup>N, and (<jats:italic>c</jats:italic>-C<jats:sub>3</jats:sub>H<jats:sub>2</jats:sub>)CH<jats:sub>2</jats:sub>. In G034.41+0.24, G327.29-0.58, G328.81+0.63, G333.13-0.43, G340.97-1.02, G351.45+0.66, and G351.77-0.54, the iCOM lines show a faint broad-line profile. Due to the offset peak positions of the blue- and redshifted emission, covering from ∼0.1 to 0.5 pc, these wings are possibly related to movements external to the compact core, such as large-scale low-velocity outflows. We have also established a correlation between the parent iCOM molecule CH<jats:sub>3</jats:sub>OH and the shock tracer SiO, reinforcing the hypothesis that shock environments provide the conditions to boost the formation of iCOMs via gas-phase reactions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this third paper of the series reporting on the reverberation mapping campaign of active galactic nuclei with asymmetric H<jats:italic>β</jats:italic> emission-line profiles, we present results for 15 Palomar–Green quasars using spectra obtained between the end of 2016–2021 May. This campaign combines long time spans with relatively high cadence. For eight objects, both the time lags obtained from the entire light curves and the measurements from individual observing seasons are provided. Reverberation mapping of nine of our targets has been attempted for the first time, while the results for six others can be compared with previous campaigns. We measure the H<jats:italic>β</jats:italic> time lags over periods of years and estimate their black hole masses. The long duration of the campaign enables us to investigate their broad-line region (BLR) geometry and kinematics for different years by using velocity-resolved lags, which demonstrate signatures of diverse BLR geometry and kinematics. The BLR geometry and kinematics of individual objects are discussed. In this sample, the BLR kinematics of Keplerian/virialized motion and inflow is more common than that of outflow.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>W-CDF-S, ELAIS-S1, and XMM-LSS will be three Deep-Drilling Fields (DDFs) of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), but their extensive multiwavelength data have not been fully utilized as done in the COSMOS field, another LSST DDF. To prepare for future science, we fit source spectral energy distributions (SEDs) from X-ray to far-infrared in these three fields mainly to derive galaxy stellar masses and star formation rates. We use <jats:monospace>CIGALE</jats:monospace> v2022.0, a code that has been regularly developed and evaluated, for the SED fitting. Our catalog includes 0.8 million sources covering 4.9 deg<jats:sup>2</jats:sup> in W-CDF-S, 0.8 million sources covering 3.4 deg<jats:sup>2</jats:sup> in ELAIS-S1, and 1.2 million sources covering 4.9 deg<jats:sup>2</jats:sup> in XMM-LSS. Besides fitting normal galaxies, we also select candidates that may host active galactic nuclei (AGNs) or are experiencing recent star formation variations and use models specifically designed for these sources to fit their SEDs; this increases the utility of our catalog for various projects in the future. We calibrate our measurements by comparison with those in well-studied smaller regions and briefly discuss the implications of our results. We also perform detailed tests of the completeness and purity of SED-selected AGNs. Our data can be retrieved from a public website.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We have obtained column density maps for an unbiased sample of 120 molecular clouds in the third quadrant of the Milky Way midplane (<jats:italic>b</jats:italic> ≤ ∣5∣°) within the Galactic longitude range from 195° to 225°, using the high-sensitivity <jats:sup>12</jats:sup>CO and <jats:sup>13</jats:sup>CO (<jats:italic>J</jats:italic> = 1 − 0) data from the Milky Way Imaging Scroll Painting (MWISP) project. The probability density functions of the molecular hydrogen column density of the clouds, N-pdfs, are fitted with both a lognormal (LN) function and a lognormal plus power-law (LN+PL) function. The molecular clouds are classified into three categories according to their shapes of N-pdfs, i.e., LN, LN+PL, and UN (unclear). About 72% of the molecular clouds fall into the LN category, while 18% and 10% fall into the LN+PL and UN categories, respectively. A PL scaling relation, <jats:inline-formula> <jats:tex-math> <?CDATA ${\sigma }_{s}\propto {N}_{{{\rm{H}}}_{2}}^{0.44}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∝</mml:mo> <mml:msubsup> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> <mml:mrow> <mml:mn>0.44</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7797ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, exists between the width of the N-pdf, <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub>, and the average column density, <jats:inline-formula> <jats:tex-math> <?CDATA ${N}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7797ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, of the molecular clouds. However, <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>s</jats:italic> </jats:sub> shows no correlation with the mass of the clouds. A correlation is found between the dispersion of normalized column density, <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>N</jats:italic>/〈N〉</jats:sub>, and the sonic Mach number, <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal M }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac7797ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>, of molecular clouds. Overall, as predicted by numerical simulations, the N-pdfs of the molecular clouds with active star formation activity tend to have N-pdfs with PL high-density tails.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The quality of astrochemical models is highly dependent on reliable binding energy (BE) values that consider the morphological and energetic variety of binding sites on the surface of ice-grain mantles. Here, we present the Binding Energy Evaluation Platform (BEEP) and database that, using quantum chemical methods, produces full BE distributions of molecules bound to an amorphous solid water (ASW) surface model. BEEP is highly automatized and allows one to sample binding sites on a set of water clusters and to compute accurate BEs. Using our protocol, we computed 21 BE distributions of interstellar molecules and radicals on an amorphized set of 15–18 water clusters of 22 molecules each. The distributions contain between 225 and 250 unique binding sites. We apply a Gaussian fit and report the mean and standard deviation for each distribution. We compare with existing experimental results and find that the low- and high-coverage experimental BEs coincide well with the high-BE tail and mean value of our distributions, respectively. Previously reported single BE theoretical values are broadly in line with ours, even though in some cases significant differences can be appreciated. We show how the use of different BE values impacts a typical problem in astrophysics, such as the computation of snow lines in protoplanetary disks. BEEP will be publicly released so that the database can be expanded to other molecules or ice models in a community effort.</jats:p>