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<jats:title>Abstract</jats:title> <jats:p>The jet composition of gamma-ray bursts (GRBs) is still an open question and the energy spectrum characteristics can provide us with evidence. GRB 210610B is a special burst with low-energy indices that are all greater than the synchrotron cutoff. We first use two empirical models, Band and CPL, and one physics model, a blackbody, to perform time-resolved spectral analysis on GRB 210610B and find that about 76.47% of the spectra need an addition thermal component to obtain a better fit. Moreover, these spectra could be well fitted by a multicolor blackbody (mBB) and the synchrotron model. We then adopt the hybrid jet model proposed by Gao &amp; Zhang to perform a “top-down” approach to diagnose the photospheric properties (<jats:italic>η</jats:italic> and <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub>) of the central engine from observational data. We find both the dimensionless entropy <jats:italic>η</jats:italic> and the magnetization parameters (1 + <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub>) are greater than 1, indicating that the Poynting flux component may play an important role in addition to the hot fireball component. Our analysis also shows that most of the spectra have a magnetization parameter (1 + <jats:italic>σ</jats:italic> <jats:sub>15</jats:sub>) ≃ 1 at ∼10<jats:sup>15</jats:sup> cm, suggesting that nonthermal emission may originate from internal shocks. Furthermore, we find that <jats:italic>α</jats:italic> and <jats:italic>E</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> show different time evolution behaviors: <jats:italic>α</jats:italic> exhibits a “hard-to-soft” behavior and moderately correlates with flux, while <jats:italic>E</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> exhibits a “tracking” behavior. The magnetic field strength <jats:italic>B</jats:italic> and the mBB parameter <jats:italic>kT</jats:italic> <jats:sub>max</jats:sub> also show a “tracking” behavior. Our results suggest that the empirical model CPL may be interpreted by an mBB.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a study of the Galactic supernova remnant (SNR) G292.0+1.8, a classic example of a core-collapse SNR that contains oxygen-rich ejecta, circumstellar material, a rapidly moving pulsar, and a pulsar wind nebula (PWN). We use hydrodynamic simulations of the remnant’s evolution to show that the SNR reverse shock is interacting with the PWN and has most likely shocked the majority of the supernova ejecta. In our models, such a scenario requires a total ejecta mass of ≲3 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> and implies that there is no significant quantity of cold ejecta in the interior of the reverse shock. In light of these results, we compare the estimated elemental masses and abundance ratios in the reverse-shocked ejecta to nucleosynthesis models, and further conclude that they are consistent with a progenitor star with an initial mass of 12–16 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>. We conclude that the progenitor of G292.0+1.8 was likely a relatively low-mass star that experienced significant mass loss through a binary interaction and would have produced a stripped-envelope supernova explosion. We also argue that the region known as the “spur” in G292.0+1.8 arises as a result of the pulsar’s motion through the supernova ejecta, and that its dynamical properties may suggest a line-of-sight component to the pulsar’s velocity, leading to a total space velocity of ∼600 km s<jats:sup>−1</jats:sup> and implying a significant natal kick. Finally, we discuss binary mass-loss scenarios relevant to G292.0+1.8 and their implications for the binary companion properties and future searches.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Ultraluminous X-ray sources (ULXs) are thought to be powerful X-ray binaries (XRBs) and may contribute significantly to the redshift-dependent X-ray emission from star-forming galaxies. We have assembled a uniform sample of 259 ULXs over the redshift range <jats:italic>z</jats:italic> = 0.002–0.51 to constrain their physical nature and their contribution to the cosmic X-ray background. The sample is constructed by crossmatching galaxies from the Sloan Digital Sky Survey with the Chandra Source Catalog and selecting off-nuclear X-ray sources after applying astrometric corrections. The fraction of contaminants is ∼30% and shows no evolution with redshift. The host-galaxy star formation rates (SFRs) are systematically elevated relative to the parent sample when matched in host stellar mass. The specific SFRs suggest a slight preference for high-mass XRBs, and the X-ray luminosity scaling relations with host-galaxy stellar mass and SFR indicate that the highest-redshift sources represent relatively luminous XRB populations that dominate their host-galaxy X-ray emission. The fraction of galaxies hosting at least one ULX of a given luminosity increases with redshift over the full range of our sample, as expected if ULXs are preferentially found in galaxies with high SFRs and low metallicities. At <jats:italic>z</jats:italic> ∼ 0.5, the ULX X-ray flux is consistent with the X-ray emission from star-forming galaxies. Moreover, ULXs may account for up to ∼40% of the integrated flux from XRBs in the normal galaxy population out to <jats:italic>z</jats:italic> ∼ 0.5, suggesting they may contribute significantly to the overall ionizing radiation from galaxies.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a detailed analysis of kinematics of the Milky Way disk in the solar neighborhood using the Gaia DR3 catalog. To determine the local kinematics of the stellar disks of the Milky Way we use a complete sample of 278,228 red giant branch (RGB) stars distributed in a cylinder, centered at the Sun with a 1 kpc radius and half-height of 0.5 kpc. We determine separately the kinematical properties of RGB stars for each Galactic hemisphere in search of possible asymmetries. The kinematical properties of the RGB stars reveal the existence of two kinematically distinct components: the thin disk with mean velocities <jats:italic>V</jats:italic> <jats:sub> <jats:italic>R</jats:italic> </jats:sub>, <jats:italic>V</jats:italic> <jats:sub> <jats:italic>ϕ</jats:italic> </jats:sub>, <jats:italic>V</jats:italic> <jats:sub> <jats:italic>Z</jats:italic> </jats:sub> of about −1, −239, 0 km s<jats:sup>−1</jats:sup>, correspondingly, and velocity dispersions <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>R</jats:italic> </jats:sub>, <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>ϕ</jats:italic> </jats:sub>, <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>Z</jats:italic> </jats:sub> of 31, 20, and 11 km s<jats:sup>−1</jats:sup>, and the Thick disk with mean velocity components of about +1, −225, 0 km s<jats:sup>−1</jats:sup>, and velocity dispersions of 49, 35, and 22 km s<jats:sup>−1</jats:sup>. We find that up to 500 pc in height above/below the Galactic plane, Thick disk stars comprise about half the stars of the disk. Such a high amount of RGB stars with Thick disk kinematics points at the secular evolution scenario origin for the Thick disk of the Milky Way.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Low-resolution LAMOST and Keck spectra of blue supergiant stars distributed over the disks of the Local Group spiral galaxies M31 and M33 are analyzed to determine stellar effective temperatures, gravities, metallicities, and reddening. Logarithmic metallicities at the center of the galaxies (in solar units) of 0.30 ± 0.09 and 0.11 ± 0.04 and metallicity gradients of −0.37 ± 0.13 dex/<jats:italic>R</jats:italic> <jats:sub>25</jats:sub> and −0.36 ± 0.16 dex/<jats:italic>R</jats:italic> <jats:sub>25</jats:sub> are measured for M31 and M33, respectively. For M33 the 2D distribution of metallicity indicates a deviation from azimuthal symmetry with an off-center peak. The flux-weighted gravity−luminosity relationship (FGLR) of blue supergiant stars is used to determine a distance modulus of 24.51 ± 0.13 mag for M31 and 24.93 ± 0.07 mag for M33. For M31 the FGLR distance agrees well with other methods. For M33 the FGLR-based distance is larger than the distances from Cepheids studies, but it is in good agreement with work on eclipsing binaries, planetary nebulae, long-period variables, and the tip of the red giant branch.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The abundance, distribution, and inner structure of satellites of galaxy clusters can be sensitive probes of the properties of dark matter. We run 30 cosmological zoom-in simulations with self-interacting dark matter (SIDM), with a velocity-dependent cross section, to study the properties of subhalos within cluster-mass hosts. We find that the abundance of subhalos that survive in the SIDM simulations are suppressed relative to their cold dark matter (CDM) counterparts. Once the population of disrupted subhalos—which may host orphan galaxies—is taken into account, satellite galaxy populations in CDM and SIDM models can be reconciled. However, even in this case, the inner structures of subhalos are significantly different in the two dark matter models. We study the feasibility of using the weak-lensing signal from the subhalo density profiles to distinguish between the cold and self-interacting dark matter while accounting for the potential contribution of orphan galaxies. We find that the effects of self-interactions on the density profile of subhalos can appear degenerate with subhalo disruption in CDM, when orphans are accounted for. With current error bars from the Subaru Hyper Suprime-Cam Strategic Program, we find that subhalos in the outskirts of clusters (where disruption is less prevalent) can be used to constrain dark matter physics. In the future, the Vera C. Rubin Observatory Legacy Survey of Space and Time will give precise measurements of the weak-lensing profile and can be used to constrain <jats:italic>σ</jats:italic> <jats:sub> <jats:italic>T</jats:italic> </jats:sub>/<jats:italic>m</jats:italic> at the ∼1 cm<jats:sup>2</jats:sup> g<jats:sup>−1</jats:sup> level at <jats:italic>v</jats:italic> ∼ 2000 km s<jats:sup>−1</jats:sup>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recent ALMA observations on disk substructures suggest the presence of embedded protoplanets in a large number of disks. The primordial configurations of these planetary systems can be deduced from the morphology of the disk substructure and serve as initial conditions for numerical investigation of their future evolution. Starting from the initial configurations of 12 multiplanetary systems deduced from ALMA disks, we carried out two-stage <jats:italic>N</jats:italic>-body simulation to investigate the evolution of the planetary systems at the disk stage, as well as the long-term orbital stability after the disk dispersal. At the disk stage, our simulation includes both the orbital migration and pebble/gas accretion effects. We found that a variety of planetary systems are produced and can be categorized into distant giant planets, Jupiter-like planets, Neptune-like planets, and distant small planets. We found that the disk-stage evolution and the final configurations are sensitive to both the initial mass assignments and viscosity. After the disk stage, we implement only mutual gravity between star and planets and introduce stochastic perturbative forces. All systems are integrated for up to 10 Gyr to test their orbital stability. Most planetary systems are found to be stable for at least 10 Gyr, with perturbative force in a reasonable range. Our result implies that a strong perturbation source such as stellar flybys is required to drive the planetary system unstable. We discuss the implications of our results on both the disk and planet observation, which may be confirmed by the next-generation telescopes such as JWST and ngVLA.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Many regions of the universe are in a state of hot, magnetized, and ionized X-ray emitting plasmas. We numerically simulated the energy spectrum of this highly viscous and conductive system. Without magnetic field, the fluctuating plasma motion decays in a relatively large viscous scale <jats:italic>l</jats:italic> <jats:sub> <jats:italic>ν</jats:italic> </jats:sub>(∼1/<jats:italic>k</jats:italic> <jats:sub> <jats:italic>ν</jats:italic> </jats:sub>). However, the magnetic field extends the viscous scale to the magnetic diffusivity one <jats:italic>l</jats:italic> <jats:sub> <jats:italic>η</jats:italic> </jats:sub>(∼1/<jats:italic>k</jats:italic> <jats:sub> <jats:italic>η</jats:italic> </jats:sub>) yielding a unique energy spectrum. Numerical simulation shows that kinetic and magnetic energy spectrum are <jats:italic>E</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> ∼ <jats:italic>k</jats:italic> <jats:sup>−3.7</jats:sup> and <jats:italic>E</jats:italic> <jats:sub> <jats:italic>M</jats:italic> </jats:sub> ∼ <jats:italic>k</jats:italic> <jats:sup>−0.85</jats:sup> in the extended viscous scale regime. To explain this extraordinary power law, we set up two simultaneous differential equations for <jats:italic>E</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> and <jats:italic>E</jats:italic> <jats:sub> <jats:italic>M</jats:italic> </jats:sub> and solved them using Eddy Damped Quasi Normal Markovianized approximation. Focusing on the most dominant terms, we analytically derived the spectrum relation <jats:inline-formula> <jats:tex-math> <?CDATA ${E}_{M}^{2}\sim {k}^{2}{E}_{V}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msubsup> <mml:mo>∼</mml:mo> <mml:msup> <mml:mrow> <mml:mi>k</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>V</mml:mi> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac66d8ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> consistent with the simulation data. We also simulated the same system with helical energy. The inversely cascaded magnetic energy makes the spectrum steeper. This inverse energy transfer, in addition to the external magnetic field and instabilities, provides us a clue to the diversified spectra characterized by <jats:italic>E</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> ∼ <jats:italic>k</jats:italic> <jats:sup>−3.8</jats:sup> − <jats:italic>k</jats:italic> <jats:sup>−3.07</jats:sup> and <jats:italic>E</jats:italic> <jats:sub> <jats:italic>M</jats:italic> </jats:sub> ∼ <jats:italic>k</jats:italic> <jats:sup>−2.17</jats:sup> − <jats:italic>k</jats:italic> <jats:sup>−0.27</jats:sup> with large magnetic Prandtl number.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a joint spectral analysis of ROSAT PSPC, Swift X-ray Telescope, and Nuclear Spectroscopic Telescope Array Focal Plane Module A/B (FPMA/B) data of the nova-like (NL) cataclysmic variables (CVs) BZ Cam and V592 Cas in the 0.1–78.0 keV band. Plasma models of collisional equilibrium fail to model the 6.0–7.0 iron line complex and continuum with <jats:inline-formula> <jats:tex-math> <?CDATA ${\chi }_{\nu }^{2}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>χ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac6616ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> larger than 2.0. Our results show nonequilibrium ionization (NEI) conditions in the X-ray plasma with temperatures of 8.2–9.4 keV and 10.0–12.9 keV for BZ Cam and V592 Cas, respectively. The centroids of He-like and H-like iron ionization lines are not at their equilibrium values as expected from NEI conditions. We find power-law spectral components that reveal the existence of scattering and Comptonization with a photon index of 1.50–1.87. We detect a P Cygni profile in the H-like iron line of BZ Cam translating to outflows of 4500–8700 km s<jats:sup>−1</jats:sup> consistent with the fast winds in the optical and UV. This is the first time such a fast collimated outflow is detected in the X-rays from an accreting CV. An iron K<jats:italic>α</jats:italic> line around 6.2–6.5 keV is found revealing the existence of reflection effects in both sources. We study the broadband noise and find that the optically thick disk truncates in BZ Cam and V592 Cas consistent with transition to an advective hot flow structure. V592 Cas also exhibits a quasiperiodic oscillation at <jats:inline-formula> <jats:tex-math> <?CDATA ${1.4}_{-0.3}^{+2.6}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1.4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.6</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac6616ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> mHz. In general, we find that the two NLs portray spectral and noise characteristics as expected from advective hot accretion flows at low radiative efficiency.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present <jats:italic>H</jats:italic>-band (1.65 <jats:italic>μ</jats:italic>m) and SOFIA HAWC+ 154 <jats:italic>μ</jats:italic>m polarization observations of the low-mass core L483. Our <jats:italic>H</jats:italic>-band observations reveal a magnetic field that is overwhelmingly in the E–W direction, which is approximately parallel to the bipolar outflow that is observed in scattered IR light and in single-dish <jats:sup>12</jats:sup>CO observations. From our 154 <jats:italic>μ</jats:italic>m data, we infer a ∼45° twist in the magnetic field within the inner 5″ (1000 au) of L483. We compare these new observations with published single-dish 350 <jats:italic>μ</jats:italic>m polarimetry and find that the 10,000 au scale <jats:italic>H</jats:italic>-band data match the smaller-scale 350 <jats:italic>μ</jats:italic>m data, indicating that the collapse of L483 is magnetically regulated on these larger scales. We also present high-resolution 1.3 mm Atacama Large Millimeter/submillimeter Array data of L483 that reveals it is a close binary star with a separation of 34 au. The plane of the binary of L483 is observed to be approximately parallel to the twisted field in the inner 1000 au. Comparing this result to the ∼1000 au protostellar envelope, we find that the envelope is roughly perpendicular to the 1000 au HAWC+ field. Using the data presented, we speculate that L483 initially formed as a wide binary and the companion star migrated to its current position, causing an extreme shift in angular momentum thereby producing the twisted magnetic field morphology observed. More observations are needed to further test this scenario.</jats:p>