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<jats:title>Abstract</jats:title> <jats:p>Submillimeter emission lines produced by the interstellar medium (ISM) are strong tracers of star formation and are some of the main targets of line intensity mapping (LIM) surveys. In this work we present an empirical multiline emission model that simultaneously covers the mean, scatter, and correlations of [C <jats:sc>ii</jats:sc>], CO <jats:italic>J</jats:italic> = 1–0 to <jats:italic>J</jats:italic> = 5–4, and [C <jats:sc>i</jats:sc>] lines in the redshift range 1 ≤ <jats:italic>z</jats:italic> ≤ 9. We assume that the galaxy ISM line emission luminosity versus halo mass relations can be described by double power laws with redshift-dependent lognormal scatter. The model parameters are then derived by fitting to the state-of-the-art semianalytic simulation results that have successfully reproduced multiple submillimeter line observations at 0 ≤ <jats:italic>z</jats:italic> ≲ 6. We cross-check the line emission statistics predicted by the semianalytic simulation and our empirical model, finding that at <jats:italic>z</jats:italic> ≥ 1 our model reproduces the simulated line intensities with fractional error less than about 10%. The fractional difference is less than 25% for the power spectra. Grounded on physically motivated and self-consistent galaxy simulations, this computationally efficient model will be helpful in forecasting ISM emission-line statistics for upcoming LIM surveys.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>High-eccentricity tidal migration is a potential formation channel for hot Jupiters. During this process, the planetary f-mode may experience a phase of diffusive growth, allowing its energy to quickly build up to large values. In Yu et al., we demonstrated that nonlinear mode interactions between a parent f-mode and daughter f- and p-modes expand the parameter space over which the diffusive growth of the parent is triggered. We extend that study by incorporating (1) the angular momentum transfer between the orbit and the mode, and consequently the evolution of the pericenter distance; (2) a prescription to regulate the nonlinear frequency shift at high parent mode energies; and (3) dissipation of the parent’s energy due to both turbulent convective damping of the daughter modes and strongly nonlinear wave-breaking events. The new ingredients allow us to follow the coupled evolution of the mode and orbit over ≳10<jats:sup>4</jats:sup> yr, covering the diffusive evolution from its onset to its termination. We find that the semimajor axis shrinks by a factor of nearly 10 over 10<jats:sup>4</jats:sup> yr, corresponding to a tidal quality factor <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal Q }\sim 10$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> <mml:mo>∼</mml:mo> <mml:mn>10</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac5627ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. The f-mode’s diffusive growth terminates while the eccentricity is still high, at around <jats:italic>e</jats:italic> = 0.8–0.95. Using these results, we revisit the eccentricity distribution of proto-hot Jupiters. We estimate that less than 1 proto-HJ with eccentricity &gt;0.9 should be expected in Kepler's data once the diffusive regime is accounted for, explaining the observed paucity of this population.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a systematic and uniform analysis of NuSTAR data of a sample of 60 SWIFT BAT-selected AGNs with 10–78 keV signal-to-noise ratio (S/N) &gt; 50, 10 of which are radio loud. We measure their high-energy cutoff <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> or coronal temperature <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> using three different spectral models to fit their NuSTAR spectra and show that a threshold in NuSTAR spectral S/N is essential for such measurements. High-energy spectral breaks are detected in the majority of the sample, and for the rest, strong constraints on <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> or <jats:italic>T</jats:italic> <jats:sub>e</jats:sub> are obtained. Strikingly, we find extraordinarily large <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> lower limits (&gt;400 keV, up to &gt;800 keV) in 10 radio-quiet sources, whereas we find none in the radio-loud sample. Consequently and surprisingly, we find a significantly larger mean <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub>/<jats:italic>T</jats:italic> <jats:sub>e</jats:sub> of radio-quiet sources compared with radio-loud ones. The reliability of these measurements is carefully inspected and verified with simulations. We find a strong positive correlation between <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> and photon index Γ, which cannot be attributed to the parameter degeneracy. The strong dependence of <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> on Γ, which could fully account for the discrepancy of the <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> distribution between radio-loud and radio-quiet sources, indicates that the X-ray coronae in AGNs with steeper hard X-ray spectra have on average higher temperature and thus smaller opacity. However, no prominent correlation is found between <jats:italic>E</jats:italic> <jats:sub>cut</jats:sub> and <jats:italic>λ</jats:italic> <jats:sub>edd</jats:sub>. In the <jats:italic>l</jats:italic>–Θ diagram, we find a considerable fraction of sources lie beyond the boundaries of forbidden regions due to runaway pair production, posing (stronger) challenges to various (flat) coronal geometries.</jats:p>

<jats:title>Abstract</jats:title> <jats:p> <jats:italic>γ</jats:italic>-ray astronomy in the energy range from MeV to GeV can provide a unique detection window for <jats:italic>γ</jats:italic>-ray bursts and other transient sources, fundamental information on particle acceleration mechanisms, MeV-blazar population studies up to <jats:italic>z</jats:italic> ∼ 4.5, and a full overview of line emission from cosmic-ray interaction. Silicon-based pair tracking telescopes rely on <jats:italic>γ</jats:italic>-ray conversion into an electron–positron pair and its tracking using a stack of silicon strips. The method presented in this work is based on a Rauch–Tung–Striebel smoother. Its internal Kalman filter enables keeping multiple hypotheses about particle tracks and implementing statistically meaningful measurement selection among hits on different planes of the tracker. The algorithm can be easily configured to work with different tracker geometries and mass models. It can be used for the exploitation of data from past and current <jats:italic>γ</jats:italic>-ray missions as well as to assess the performances of new pair-tracking telescopes. The proposed method has been validated on Astrorivelatore Gamma a Immagini Leggero data and then used to investigate the performances of both e-ASTROGAM and All-Sky-ASTROGAM telescopes. The algorithm efficiency and its accuracy in estimating both the photon direction and energy were evaluated on <jats:italic>γ</jats:italic>-ray events simulated at different energies in the range between 30 MeV and 3 GeV. The point-spread function of each tracker was then compared with its angular resolution limit showing both the expected performances of the instrument and the margin of improvement that could be obtained by optimizing the reconstruction method.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The dissipative mechanism in weakly collisional plasma is a topic that pervades decades of studies without a consensus solution. We compare several energy dissipation estimates based on energy transfer processes in plasma turbulence and provide justification for the pressure–strain interaction as a direct estimate of the energy dissipation rate. The global and scale-by-scale energy balances are examined in 2.5D and 3D kinetic simulations. We show that the global internal energy increase and the temperature enhancement of each species are directly tracked by the pressure–strain interaction. The incompressive part of the pressure–strain interaction dominates over its compressive part in all simulations considered. The scale-by-scale energy balance is quantified by scale filtered Vlasov–Maxwell equations, a kinetic plasma approach, and the lag dependent von Kármán–Howarth equation, an approach based on fluid models. We find that the energy balance is exactly satisfied across all scales, but the lack of a well-defined inertial range influences the distribution of the energy budget among different terms in the inertial range. Therefore, the widespread use of the Yaglom relation in estimating the dissipation rate is questionable in some cases, especially when the scale separation in the system is not clearly defined. In contrast, the pressure–strain interaction balances exactly the dissipation rate at kinetic scales regardless of the scale separation.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>As the only known intelligent civilization, human beings are always curious about the existence of other communicating extraterrestrial intelligent civilizations (CETIs). Based on the latest astrophysical information, we carry out Monte Carlo simulations to estimate the number of possible CETIs within our Galaxy and the communication probability among them. Two poorly known parameters have a great impact on the results. One is the probability of life appearing on terrestrial planets and eventually evolving into a CETI (<jats:italic>f</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub>), and the other determines at what stage of their host star’s evolution CETIs would be born (<jats:italic>F</jats:italic>). In order to ensure the completeness of the simulation, we consider a variety of combinations of <jats:italic>f</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> and <jats:italic>F</jats:italic>. Our results indicate that for optimistic situations (e.g., <jats:italic>F</jats:italic> = 25% and <jats:italic>f</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> = 0.1%), there could be <jats:inline-formula> <jats:tex-math> <?CDATA ${\mathrm{42,777}}_{-369}^{+267}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>42,777</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>369</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>267</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn1.gif" xlink:type="simple" /> </jats:inline-formula> CETIs and they need to survive for <jats:inline-formula> <jats:tex-math> <?CDATA ${3}_{-2}^{+17}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>17</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn2.gif" xlink:type="simple" /> </jats:inline-formula> yr (<jats:inline-formula> <jats:tex-math> <?CDATA ${2000}_{-1400}^{+2000}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>2000</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1400</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2000</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn3.gif" xlink:type="simple" /> </jats:inline-formula> yr) to achieve one-way communication (two-way communication). In this case, human beings need to survive <jats:inline-formula> <jats:tex-math> <?CDATA ${0.3}_{-0.298}^{+0.6}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.298</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.6</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn4.gif" xlink:type="simple" /> </jats:inline-formula> Myr to receive one alien signal. For pessimistic situations (e.g., <jats:italic>F</jats:italic> = 75% and <jats:italic>f</jats:italic> <jats:sub> <jats:italic>c</jats:italic> </jats:sub> = 0.001%), only <jats:inline-formula> <jats:tex-math> <?CDATA ${111}_{-17}^{+28}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>111</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>17</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>28</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn5.gif" xlink:type="simple" /> </jats:inline-formula> CETIs could be born and they need to survive for <jats:inline-formula> <jats:tex-math> <?CDATA ${0.8}_{-0.796}^{+1.2}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.796</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>1.2</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn6.gif" xlink:type="simple" /> </jats:inline-formula> Myr (<jats:inline-formula> <jats:tex-math> <?CDATA ${0.9}_{-0.88}^{+4.1}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>0.9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.88</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.1</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn7.gif" xlink:type="simple" /> </jats:inline-formula> Myr) to achieve one-way communication (two-way communication). In this case, human beings need to survive <jats:inline-formula> <jats:tex-math> <?CDATA ${50}_{-49.6}^{+250}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>50</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>49.6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>250</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac561dieqn8.gif" xlink:type="simple" /> </jats:inline-formula> Myr to receive one signal from other CETIs. Our results may quantitatively explain why we have not detected any alien signals so far. The uncertainty of the results has been discussed in detail and would be alleviated with the further improvement of our astronomical observation ability in the future.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The number of potentially habitable planets continues to increase, but we lack the time and resources to characterize all of them. With ∼30 known potentially habitable planets and an ever-growing number of candidate and confirmed planets, a robust statistical framework for prioritizing characterization of these planets is desirable. Using the ∼2 Gyr it took life on Earth to make a detectable impact on the atmosphere as a benchmark, we use a Bayesian statistical method to determine the probability that a given radius around a star has been continuously habitable for 2 Gyr. We perform this analysis on nine potentially habitable exoplanets with planetary radii &lt;1.8 <jats:italic>R</jats:italic> <jats:sub>⊕</jats:sub> and/or planetary masses &lt;10 <jats:italic>M</jats:italic> <jats:sub>⊕</jats:sub> around nine low-mass host stars (∼0.5–1.1 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) with measured stellar mass and metallicity, as well as Venus, Earth, and Mars. Ages for the host stars are generated by the analysis. The technique is also used to provide age estimates for 2768 low-mass stars (0.5–1.3 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) in the TESS Continuous Viewing Zones.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The spatial range for feedback from star formation varies from molecular cloud disruption on parsec scales to supershells and disk blowout on kiloparsec scales. The relative amounts of energy and momentum given to these scales are important for understanding the termination of star formation in any one region and the origin of interstellar turbulence and disk stability in galaxies as a whole. Here, we measure, for 11 THINGS galaxies, the excess kinetic energy, velocity dispersion, and surface density of H <jats:sc>i</jats:sc> gas associated with regions of excess star formation, where the excess is determined from the difference between the observed local value and the azimuthal average. We find small decreases in the excess kinetic energy and velocity dispersion in regions of excess star formation rate density, suggesting that most of the feedback energy does not go into local H <jats:sc>i</jats:sc> motion. Most likely, it disrupts molecular clouds and dissipates rapidly at high gas density. Some could also be distributed over larger regions, filling in spaces between the peaks of star formation and contributing to other energy sources from self-gravity and spiral arm shocks.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Here we describe a new study of the supernova remnants (SNRs) and SNR candidates in nearby face-on spiral galaxy M83, based primarily on MUSE integral field spectroscopy. Our revised catalog of SNR candidates in M83 has 366 objects, 81 of which are reported here for the first time. Of these, 229 lie within the MUSE observation region, 160 of which have spectra with [S <jats:sc>ii</jats:sc>]:H<jats:italic>α</jats:italic> ratios exceeding 0.4, the value generally accepted as confirmation that an emission nebula is shock-heated. Combined with 51 SNR candidates outside the MUSE region with high [S <jats:sc>ii</jats:sc>]:H<jats:italic>α</jats:italic> ratios, there are 211 spectroscopically confirmed SNRs in M83, the largest number of confirmed SNRs in any external galaxy. MUSE’s combination of relatively high spectral resolution and broad wavelength coverage has allowed us to explore two other properties of SNRs that could serve as the basis of future SNR searches. Specifically, most of the objects identified as SNRs on the basis of [S <jats:sc>ii</jats:sc>]:H<jats:italic>α</jats:italic> ratios exhibit more velocity broadening and lower ratios of [S <jats:sc>iii</jats:sc>]:[S <jats:sc>ii</jats:sc>] emission than H <jats:sc>ii</jats:sc> regions. A search for nebulae with the very broad emission lines expected from young, rapidly expanding remnants revealed none, except for the previously identified B12-174a. The SNRs identified in M83 are, with few exceptions, middle-aged interstellar medium (ISM) dominated ones. Smaller-diameter candidates show a larger range of velocity broadening and a larger range of gas densities than the larger-diameter objects, as expected if the SNRs expanding into denser gas brighten and then fade from view at smaller diameters than those expanding into a more tenuous ISM.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigate the formation of jellyfish galaxies using radiation-hydrodynamic simulations of gas-rich dwarf galaxies with a multiphase interstellar medium (ISM). We find that the ram-pressure-stripped (RPS) ISM is the dominant source of molecular clumps in the near wake within 10 kpc from the galactic plane, while in situ formation is the major channel for dense gas in the distant tail of the gas-rich galaxy. Only 20% of the molecular clumps in the near wake originate from the intracluster medium (ICM); however, the fraction reaches 50% in the clumps located at 80 kpc from the galactic center since the cooling time of the RPS gas tends to be short owing to the ISM–ICM mixing (≲10 Myr). The tail region exhibits a star formation rate of 0.001–0.01 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>, and most of the tail stars are born in the stripped wake within 10 kpc from the galactic plane. These stars induce bright H<jats:italic>α</jats:italic> blobs in the tail, while H<jats:italic>α</jats:italic> tails fainter than 6 × 10<jats:sup>38</jats:sup> erg s<jats:sup>−1</jats:sup> kpc<jats:sup>−2</jats:sup> are mostly formed via collisional radiation and heating due to mixing. We also find that the stripped tails have intermediate X-ray-to-H<jats:italic>α</jats:italic> surface brightness ratios (1.5 ≲ <jats:italic>F</jats:italic> <jats:sub>X</jats:sub>/<jats:italic>F</jats:italic> <jats:sub>H<jats:italic>α</jats:italic> </jats:sub> ≲ 20), compared to the ISM (≲1.5) or pure ICM (≫20). Our results suggest that jellyfish features emerge when the ISM from gas-rich galaxies is stripped by strong ram pressure, mixes with the ICM, and enhances the cooling in the tail.</jats:p>