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<jats:title>Abstract</jats:title> <jats:p>Nonthermal desorption of molecules from icy grain surfaces is required to explain molecular line observations in the cold gas of star-forming regions. Chemical desorption is one of the nonthermal desorption processes and is driven by the energy released by chemical reactions. After an exothermic surface reaction, the excess energy is transferred to products’ translational energy in the direction perpendicular to the surface, leading to desorption. The desorption probability of product species, especially that of product species from water-ice surfaces, is not well understood. This uncertainty limits our understanding of the interplay between gas-phase and ice-surface chemistry. In the present work, we constrain the desorption probability of H<jats:sub>2</jats:sub>S and PH<jats:sub>3</jats:sub> per reaction event on porous amorphous solid water (ASW) by numerically simulating previous laboratory experiments. Adopting the microscopic kinetic Monte Carlo method, we find that the desorption probabilities of H<jats:sub>2</jats:sub>S and PH<jats:sub>3</jats:sub> from porous ASW per hydrogen-addition event of the precursor species are 3% ± 1.5% and 4% ± 2%, respectively. These probabilities are consistent with a theoretical model of chemical desorption proposed in the literature if ∼7% of energy released by the reactions is transferred to the translational excitation of the products. As a byproduct, we find that approximately 70% (40%) of adsorption sites for atomic H on porous ASW should have a binding energy lower than ∼300 K (∼200 K). The astrochemical implications of our findings are briefly discussed.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Discovered in 2011 with LOFAR, the 15 Jy low-frequency radio transient ILT J225347+862146 heralds a potentially prolific population of radio transients at &lt;100 MHz. However, subsequent transient searches in similar parameter space yielded no detections. We test the hypothesis that these surveys at comparable sensitivity have missed the population due to mismatched survey parameters. In particular, the LOFAR survey used only 195 kHz of bandwidth at 60 MHz, while other surveys were at higher frequencies or had wider bandwidth. Using 137 hr of all-sky images from the Owens Valley Radio Observatory Long Wavelength Array, we conduct a narrowband transient search at ∼10 Jy sensitivity with timescales from 10 minutes to 1 day and a bandwidth of 722 kHz at 60 MHz. To model the remaining survey selection effects, we introduce a flexible Bayesian approach for inferring transient rates. We do not detect any transient and find compelling evidence that our nondetection is inconsistent with the detection of ILT J225347+862146. Under the assumption that the transient is astrophysical, we propose two hypotheses that may explain our nondetection. First, the transient population associated with ILT J225347+862146 may have a low all-sky density and display strong temporal clustering. Second, ILT J225347+862146 may be an extreme instance of the fluence distribution, of which we revise the surface density estimate at 15 Jy to 1.1 × 10<jats:sup>−7</jats:sup> deg<jats:sup>−2</jats:sup> with a 95% credible interval of (3.5 × 10<jats:sup>−12</jats:sup>, 3.4 × 10<jats:sup>−7</jats:sup>) deg<jats:sup>−2</jats:sup>. Finally, we find a previously identified object coincident with ILT J225347+862146 to be an M dwarf at 420 pc.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We forecast the number of galaxy clusters that can be detected via the thermal Sunyaev–Zel’dovich (tSZ) signals by future cosmic microwave background (CMB) experiments, primarily the wide area survey of the CMB-S4 experiment but also CMB-S4's smaller de-lensing survey and the proposed CMB-HD experiment. We predict that CMB-S4 will detect 75,000 clusters with its wide survey of <jats:italic>f</jats:italic> <jats:sub>sky</jats:sub> = 50% and 14,000 clusters with its deep survey of <jats:italic>f</jats:italic> <jats:sub>sky</jats:sub> = 3%. Of these, approximately 1350 clusters will be at <jats:italic>z</jats:italic> ≥ 2, a regime that is difficult to probe by optical or X-ray surveys. We assume CMB-HD will survey the same sky as the S4-Wide, and find that CMB-HD will detect three times more overall and an order of magnitude more <jats:italic>z</jats:italic> ≥ 2 clusters than CMB-S4. These results include galactic and extragalactic foregrounds along with atmospheric and instrumental noise. Using CMB-cluster lensing to calibrate the cluster tSZ–mass scaling relation, we combine cluster counts with primary CMB to obtain cosmological constraints for a two-parameter extension of the standard model (ΛCDM + ∑<jats:italic>m</jats:italic> <jats:sub> <jats:italic>ν</jats:italic> </jats:sub> + <jats:italic>w</jats:italic> <jats:sub>0</jats:sub>). In addition to constraining <jats:italic>σ</jats:italic>(<jats:italic>w</jats:italic> <jats:sub>0</jats:sub>) to ≲1%, we find that both surveys can enable a ∼2.5–4.5<jats:italic>σ</jats:italic> detection of ∑<jats:italic>m</jats:italic> <jats:sub> <jats:italic>ν</jats:italic> </jats:sub>, substantially strengthening CMB-only constraints. We also study the evolution of the intracluster medium by modeling the cluster virialization v(<jats:italic>z</jats:italic>) and find tight constraints from CMB-S4, with further factors of three to four improvement for CMB-HD.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Transiting planets at young ages are key targets for improving our understanding of the evolution of exo-atmospheres. We present results of a new X-ray observation of V 1298 Tau with XMM-Newton, aimed to determine more accurately the high-energy irradiation of the four planets orbiting this pre-main-sequence star, and the possible variability due to magnetic activity on short and long timescales. Following the first measurements of planetary masses in the V 1298 Tau system, we revise early guesses of the current escape rates from the planetary atmospheres, employing our updated atmospheric evaporation models to predict the future evolution of the system. Contrary to previous expectations, we find that the two outer Jupiter-sized planets will not be affected by any evaporation on Gyr timescales, and the same occurs for the two smaller inner planets, unless their true masses are lower than ∼40 <jats:italic>M</jats:italic> <jats:sub>⊕</jats:sub>. These results confirm that relatively massive planets can reach their final position in the mass–radius diagram very early in their evolutionary history.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The cross sections and rate coefficients for inelastic processes in low-energy collisions of nickel atoms and positive ions with hydrogen atoms and negative ions are calculated for the collisional energy range 10<jats:sup>−4</jats:sup>–100 eV and for the temperature range 1000–10,000 K. 74 covalent and three ionic states correlated to 11 molecular symmetries are considered. 3380 partial inelastic processes are treated in total. The study of nickel–hydrogen collisions is performed by the quantum model methods within the Born–Oppenheimer formalism. The electronic structure of the collisional quasimolecule is calculated by the semiempirical asymptotic method for each considered molecular symmetry. For nuclear dynamic calculations the simplified method in combination with the Landau–Zener model is used. Nuclear dynamics within each considered symmetry is treated separately, and the total rate coefficients for each inelastic process have been summed over all symmetries. The largest values of the rate coefficients (exceeding 10<jats:sup>−8</jats:sup> cm<jats:sup>3</jats:sup> s<jats:sup>−1</jats:sup>) correspond to the mutual neutralization processes in collisions Ni<jats:sup>+</jats:sup>(3<jats:italic>d</jats:italic> <jats:sup>9</jats:sup> <jats:sup>2</jats:sup> <jats:italic>D</jats:italic>) + H<jats:sup>−</jats:sup>(1<jats:italic>s</jats:italic> <jats:sup>2</jats:sup> <jats:sup>1</jats:sup> <jats:italic>S</jats:italic>) (the ground ionic state being the initial state), as well as in Ni<jats:sup>+</jats:sup>(3<jats:italic>d</jats:italic> <jats:sup>8</jats:sup>4<jats:italic>s</jats:italic> <jats:sup>4,2</jats:sup> <jats:italic>F</jats:italic>) + H<jats:sup>−</jats:sup>(1<jats:italic>s</jats:italic> <jats:sup>2</jats:sup> <jats:sup>1</jats:sup> <jats:italic>S</jats:italic>) (the first excited and the second excited ionic states being the initial states) collisions. At the temperature of 6000 K, the rate coefficients with large magnitudes have the values from the ranges (1.35−5.87) × 10<jats:sup>−8</jats:sup> cm<jats:sup>3</jats:sup> s<jats:sup>−1</jats:sup> and (1.02−6.77) × 10<jats:sup>−8</jats:sup> cm<jats:sup>3</jats:sup> s<jats:sup>−1</jats:sup>, respectively. The calculated rate coefficients with large and moderate values are important for non–local thermodynamic equilibrium stellar atmosphere modeling.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Collisions with ice-covered silica grains are studied using molecular-dynamics simulation, with a focus on the influence of the impact parameter on the collision dynamics. The ice mantle induces an attractive interaction between the colliding grains, which is caused by the melting of the mantles in the collision zone and their fusion. For noncentral collisions, this attractive interaction leads to a deflection of the grain trajectories and, at smaller velocities, to the agglomeration (“sticking”) of the colliding grains. The bouncing velocity, which is defined as the smallest velocity at which grains bounce off each other rather than stick, shows only a negligible dependence on the impact parameter. Close to the bouncing velocity, a temporary bridge builds up between the colliding grains, which, however, ruptures when the collided grains separate and relaxes to the grains. At higher velocities, the ice in the collision zone is squeezed out from between the silica cores, forming an expanding disk, which ultimately tears and dissolves into a multitude of small droplets. An essential fraction of the ice cover in the collision zone is then set free to space. Astrophysical implications include the possibility that organic species that might be present in small concentrations on the ice surface or at the ice–silica interface are liberated to space in such noncentral collisions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>At the end of 2020 September, the Parker Solar Probe (PSP) and BepiColombo were radially aligned: PSP was orbiting near 0.17 au and BepiColombo near 0.6 au. This geometry is of particular interest for investigating the evolution of solar wind properties at different heliocentric distances by observing the same solar wind plasma parcels. In this work, we use the magnetic field observations from both spacecraft to characterize both the topology of the magnetic field at different heliocentric distances (scalings, high-order statistics, and multifractal features) and its evolution when moving from near-Sun to far-Sun locations. We observe a breakdown of the statistical self-similar nature of the solar wind plasma with an increase in the efficiency of the nonlinear energy cascade mechanism when moving away from the Sun. We find a complex organization of large field gradients to dissipate the excess of kinetic energy across the inertial range near the Sun, whereas the topological organization of small fluctuations is still primarily responsible for the energy transfer rate at 0.6 au. These results provide, for the first time, evidence of the different roles of dissipation mechanisms near and far away from the Sun.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We report CO(5 → 4) and CO(6 → 5) line observations in the dusty starbursting galaxy CRLE (<jats:italic>z</jats:italic> = 5.667) and the main-sequence (MS) galaxy HZ10 (<jats:italic>z</jats:italic> = 5.654) with the Northern Extended Millimeter Array. CRLE is the most luminous <jats:italic>z</jats:italic> &gt; 5 starburst in the COSMOS field and HZ10 is the most gas-rich “normal” galaxy currently known at <jats:italic>z</jats:italic> &gt; 5. We find line luminosities for CO(5 → 4) and CO(6 → 5) of (4.9 ± 0.5) and (3.8 ± 0.4) × 10<jats:sup>10</jats:sup> K km s<jats:sup>−1</jats:sup> pc<jats:sup>2</jats:sup> for CRLE and upper limits of &lt; 0.76 and &lt; 0.60 × 10<jats:sup>10</jats:sup> K km s<jats:sup>−1</jats:sup> pc<jats:sup>2</jats:sup> for HZ10, respectively. The CO excitation of CRLE appears comparable to other <jats:italic>z</jats:italic> &gt; 5 dusty star-forming galaxies. For HZ10, these line luminosity limits provide the first significant constraints of this kind for an MS galaxy at <jats:italic>z</jats:italic> &gt; 5. We find the upper limit of <jats:inline-formula> <jats:tex-math> <?CDATA ${L}_{5\to 4}^{{\prime} }/{L}_{2\to 1}^{{\prime} }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>L</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>5</mml:mn> <mml:mo>→</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo accent="true">′</mml:mo> </mml:mrow> </mml:msubsup> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msubsup> <mml:mrow> <mml:mi>L</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>→</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mo accent="true">′</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac403aieqn1.gif" xlink:type="simple" /> </jats:inline-formula> in HZ10 could be similar to the average value for MS galaxies around <jats:italic>z</jats:italic> ≈ 1.5, suggesting that MS galaxies with comparable gas excitation may already have existed one billion years after the Big Bang. For CRLE we determine the most likely values for the H<jats:sub>2</jats:sub> density, kinetic temperature, and dust temperature based on excitation modeling of the CO line ladder. We also derive a total gas mass of (7.1 ± 1.3) × 10<jats:sup>10</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>. Our findings provide some of the currently most detailed constraints on the gas excitation that sets the conditions for star formation in a galaxy protocluster environment at <jats:italic>z</jats:italic> &gt; 5.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We utilize the ALMA-MaNGA QUEnch and STar formation (ALMaQUEST) survey to investigate the kpc-scale scaling relations, presented as the resolved star-forming MS (rSFMS: Σ<jats:sub>SFR</jats:sub> versus Σ<jats:sub>*</jats:sub>), the resolved Schmidt–Kennicutt relation (rSK: Σ<jats:sub>SFR</jats:sub> versus <jats:inline-formula> <jats:tex-math> <?CDATA ${{\rm{\Sigma }}}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">Σ</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="apjac4cccieqn1.gif" xlink:type="simple" /> </jats:inline-formula>), and the resolved molecular gas MS (rMGMS: <jats:inline-formula> <jats:tex-math> <?CDATA ${{\rm{\Sigma }}}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">Σ</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="apjac4cccieqn2.gif" xlink:type="simple" /> </jats:inline-formula> versus Σ<jats:sub>*</jats:sub>), for 11,478 star-forming and 1414 retired spaxels (oversampled by a factor of ∼20) located in 22 GV and 12 MS galaxies. For a given galaxy type (MS or GV), the retired spaxels are found to be offset from the sequences formed by the star-forming spaxels on the rSFMS, rSK, and rMGMS planes, toward lower absolute values of sSFR, SFE, and <jats:inline-formula> <jats:tex-math> <?CDATA ${f}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>f</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="apjac4cccieqn3.gif" xlink:type="simple" /> </jats:inline-formula> by ∼1.1, 0.6, and 0.5 dex. The scaling relations for GV galaxies are found to be distinct from that of the MS galaxies, even if the analyses are restricted to the star-forming spaxels only. It is found that, for star-forming spaxels, sSFR, SFE, and <jats:inline-formula> <jats:tex-math> <?CDATA ${f}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>f</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="apjac4cccieqn4.gif" xlink:type="simple" /> </jats:inline-formula> in GV galaxies are reduced by ∼0.36, 0.14, and 0.21 dex, respectively, compared to those in MS galaxies. Therefore, the suppressed sSFR/SFE/<jats:italic>f</jats:italic> <jats:sub>gas</jats:sub> in GV galaxies is associated with not only an increased proportion of retired regions in GV galaxies but also a depletion of these quantities in star-forming regions. Finally, the reduction of SFE and <jats:inline-formula> <jats:tex-math> <?CDATA ${f}_{{{\rm{H}}}_{2}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>f</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="apjac4cccieqn5.gif" xlink:type="simple" /> </jats:inline-formula> in GV galaxies relative to MS galaxies is seen in both bulge and disk regions (albeit with larger uncertainties), suggesting that, statistically, quenching in the GV population may persist from the inner to the outer regions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present 75 near-infrared (NIR; 0.8−2.5 <jats:italic>μ</jats:italic>m) spectra of 34 stripped-envelope core-collapse supernovae (SESNe) obtained by the Carnegie Supernova Project-II (CSP-II), encompassing optical spectroscopic Types IIb, Ib, Ic, and Ic-BL. The spectra range in phase from pre-maximum to 80 days past maximum. This unique data set constitutes the largest NIR spectroscopic sample of SESNe to date. NIR spectroscopy provides observables with additional information that is not available in the optical. Specifically, the NIR contains the strong lines of He <jats:sc>i</jats:sc> and allows a more detailed look at whether Type Ic supernovae are completely stripped of their outer He layer. The NIR spectra of SESNe have broad similarities, but closer examination through statistical means reveals a strong dichotomy between NIR “He-rich” and “He-poor” SNe. These NIR subgroups correspond almost perfectly to the optical IIb/Ib and Ic/Ic-BL types, respectively. The largest difference between the two groups is observed in the 2 <jats:italic>μ</jats:italic>m region, near the He <jats:sc>i</jats:sc> <jats:italic>λ</jats:italic>2.0581 <jats:italic>μ</jats:italic>m line. The division between the two groups is <jats:italic>not</jats:italic> an arbitrary one along a continuous sequence. Early spectra of He-rich SESNe show much stronger He <jats:sc>i</jats:sc> <jats:italic>λ</jats:italic>2.0581 <jats:italic>μ</jats:italic>m absorption compared to the He-poor group, but with a wide range of profile shapes. The same line also provides evidence for trace amounts of He in half of our SNe in the He-poor group.</jats:p>