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<jats:title>Abstract</jats:title> <jats:p>The <jats:italic>L</jats:italic>–<jats:italic>σ</jats:italic> relation of H <jats:sc>ii</jats:sc> galaxies (HIIGx) calibrated by a distance indicator is a reliable standard candle for measuring the Hubble constant <jats:italic>H</jats:italic> <jats:sub>0</jats:sub>. The most straightforward calibration technique anchors them with the first tier of distance ladders from the same galaxies. Recently another promising method that uses the cosmological model–independent cosmic chronometers as a calibrator has been proposed. We promote this technique by removing the assumptions about the cosmic flatness and using a nonparametric artificial neural network for the data reconstruction process. We observe a correlation between the cosmic curvature density parameter and the slope of the <jats:italic>L</jats:italic>–<jats:italic>σ</jats:italic> relation, thereby improving the reliability of the calibration. Using the calibrated HIIGx Hubble diagram, we obtain a Type Ia supernovae Hubble diagram free of the conventional assumption about <jats:italic>H</jats:italic> <jats:sub>0</jats:sub>. Finally we get a value of <jats:inline-formula> <jats:tex-math> <?CDATA ${H}_{0}={65.9}_{-2.9}^{+3.0}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>H</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>65.9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2.9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>3.0</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em" /> <mml:mi>km</mml:mi> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi>Mpc</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac85aaieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, which is compatible with the latest Planck 18 measurement.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Based on 16,283 early-type galaxies (ETGs) in 0.025 ≤ <jats:italic>z</jats:italic> <jats:sub>spec</jats:sub> &lt; 0.055 from Sloan Digital Sky Survey data, we show that the fundamental plane (FP) of ETGs is not a plane in the strict sense but is a curved surface with a twisted shape whose orthogonal direction to the surface is shifted as the central velocity dispersion (<jats:italic>σ</jats:italic> <jats:sub>0</jats:sub>) or mean surface brightness within the half-light radius (<jats:italic>μ</jats:italic> <jats:sub> <jats:italic>e</jats:italic> </jats:sub>) changes. When ETGs are divided into subsamples according to <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub>, the coefficient of <jats:italic>μ</jats:italic> <jats:sub> <jats:italic>e</jats:italic> </jats:sub> of the FP increases, whereas the zero-point of the FP decreases at higher <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub>. Taking the <jats:italic>z</jats:italic> band as an example, the coefficient of <jats:italic>μ</jats:italic> <jats:sub> <jats:italic>e</jats:italic> </jats:sub> rises from 0.28 to 0.36 as <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub> increases from ∼100 to ∼300 km s<jats:sup>−1</jats:sup>. At the same time, the zero-point of the FP falls from −7.5 to −9.0 in the same <jats:italic>σ</jats:italic> <jats:sub>0</jats:sub> range. The consistent picture on the curved nature of the FP is also reached by inspecting changes in the FP coefficients for ETG subsamples with different <jats:italic>μ</jats:italic> <jats:sub> <jats:italic>e</jats:italic> </jats:sub>. By examining scaling relations that are projections of the FP, we suggest that the warped nature of the FP may originate from dry merger effects that are imprinted more prominently in ETGs with higher masses.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Identifying the young optically visible population in a star-forming region is essential for fully understanding the star formation event. In this paper, we identify 211 candidate members of the Perseus molecular cloud based on Gaia astrometry. We use LAMOST spectra to confirm that 51 of these candidates are new members, bringing the total census of known members to 856. The newly confirmed members are less extincted than previously known members. Two new stellar aggregates are identified in our updated census. With the updated member list, we obtain a statistically significant distance gradient of 4.84 pc deg<jats:sup>−1</jats:sup> from west to east. Distances and extinction corrected color–magnitude diagrams indicate that NGC 1333 is significantly younger than IC 348 and the remaining cloud regions. The disk fraction in NGC 1333 is higher than elsewhere, consistent with its youngest age. The star formation scenario in the Perseus molecular cloud is investigated and the bulk motion of the distributed population is consistent with the cloud being swept away by the Per-Tau Shell.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Polarized Galactic synchrotron emission is an undesirable foreground for cosmic microwave background experiments observing at frequencies &lt;150 GHz. We perform a combined analysis of observational data at 1.4, 2.3, 23, 30, and 33 GHz to quantify the spatial variation of the polarized synchrotron spectral index, <jats:italic>β</jats:italic> <jats:sup>pol</jats:sup>, on ∼3.°5 scales. We compare results from different data combinations to address limitations and inconsistencies present in these public data, and form a composite map of <jats:italic>β</jats:italic> <jats:sup>pol</jats:sup>. Data quality masking leaves 44% sky coverage (73% for ∣<jats:italic>b</jats:italic>∣ &gt; 45°). Generally −3.2 &lt; <jats:italic>β</jats:italic> <jats:sup>pol</jats:sup> ≲ −3 in the inner Galactic plane and spurs, but the Fan Region in the outer galaxy has a flatter index. We find a clear spectral index steepening with increasing latitude south of the Galactic plane with Δ<jats:italic>β</jats:italic> <jats:sup>pol</jats:sup> = 0.4, and a smaller steepening of 0.25 in the north. Near the south Galactic pole the polarized synchrotron spectral index is <jats:italic>β</jats:italic> <jats:sup>pol</jats:sup> ≈ −3.4. Longitudinal spectral index variations of Δ<jats:italic>β</jats:italic> <jats:sup>pol</jats:sup> ∼ 0.1 about the latitudinal mean are also detected. Within the BICEP2/Keck survey footprint, we find consistency with a constant value, <jats:italic>β</jats:italic> <jats:sup>pol</jats:sup> = −3.25 ± 0.04 (statistical) ±0.02 (systematic). We compute a map of the frequency at which synchrotron and thermal dust emission contribute equally to the total polarized foreground. The limitations and inconsistencies among data sets encountered in this work make clear the value of additional independent surveys at multiple frequencies, especially between 10 and 20 GHz, provided these surveys have sufficient sensitivity and control of instrumental systematic errors.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Using data from the Sloan Digital Sky Survey Legacy Survey, we study the alignment of luminous galaxies with spectroscopic data with the surrounding larger-scale structure as defined by galaxies with only photometric data. We find that galaxies from the red sequence have a statistically significant tendency for their apparent long axes to align parallel to the projected surrounding structure. Red galaxies more luminous than the median of our sample (<jats:italic>M</jats:italic> <jats:sub> <jats:italic>r</jats:italic> </jats:sub> &lt; −21.78) have a mean alignment angle 〈Φ〉 &lt; 45°, indicating preferred parallel alignment, at a significance level &gt;4.5<jats:italic>σ</jats:italic> on projected scales 0.1 Mpc &lt; <jats:italic>r</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> ≤ 7.5 Mpc. Fainter red galaxies have 〈Φ〉 &lt; 45° at a significance level &gt;4.3<jats:italic>σ</jats:italic> at scales 1 Mpc &lt; <jats:italic>r</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> &lt; 3 Mpc. At a projected scale <jats:italic>r</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> = 3.0 Mpc, the mean alignment angle decreases steadily with increasing luminosity for red galaxies with <jats:italic>M</jats:italic> <jats:sub> <jats:italic>r</jats:italic> </jats:sub> ≲ −22.5, reaching 〈Φ〉 = 40.°49 ± 0.°56 for the most luminous 1% (<jats:italic>M</jats:italic> <jats:sub> <jats:italic>r</jats:italic> </jats:sub> ∼ −23.57). Galaxies from the blue sequence show no statistically significant tendency for their axes to align with larger-scale structure, regardless of galaxy luminosity. Galaxies in higher-density regions do not show a statistically significant difference in the mean alignment angle from galaxies in lower-density regions; this holds true for the faint blue, luminous blue, faint red, and luminous red subsets.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The contribution of galactic supernova remnants (SNRs) to the origin of cosmic rays (CRs) is an important open question in modern astrophysics. Broadband nonthermal emission is a useful proxy for probing the energy budget and production history of CRs in SNRs. We conduct hydrodynamic simulations to model the long-term SNR evolution from explosion all the way to the radiative phase (or 3 × 10<jats:sup>5</jats:sup> yr at maximum) and compute the time evolution of the broadband nonthermal spectrum to explore its potential applications on constraining the surrounding environments, as well as the natures and mass-loss histories, of the SNR progenitors. A parametric survey is performed on the ambient environments separated into two main groups, namely, a homogeneous medium with a uniform gas density and one with the presence of a circumstellar structure created by the stellar wind of a massive red supergiant progenitor star. Our results reveal a highly diverse evolution history of the nonthermal emission closely correlated to the environmental characteristics of an SNR. Up to the radiative phase, the roles of CR reacceleration and ion−neutral wave damping on the spectral evolution are investigated. Finally, we make an assessment of the future prospect of SNR observations by the next-generation hard X-ray space observatory FORCE and predict what we can learn from their comparison with our evolution models.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We perform a high-resolution, 2D, fully kinetic numerical simulation of a turbulent plasma system with observation-driven conditions, in order to investigate the interplay between turbulence, magnetic reconnection, and particle heating from ion to subelectron scales in the near-Sun solar wind. We find that the power spectra of the turbulent plasma and electromagnetic fluctuations show multiple power-law intervals down to scales smaller than the electron gyroradius. Magnetic reconnection is observed to occur in correspondence of current sheets with a thickness of the order of the electron inertial length, which form and shrink owing to interacting ion-scale vortices. In some cases, both ion and electron outflows are observed (the classic reconnection scenario), while in others—typically for the shortest current sheets—only electron jets are present (“electron-only reconnection”). At the onset of reconnection, the electron temperature starts to increase and a strong parallel temperature anisotropy develops. This suggests that in strong turbulence electron-scale coherent structures may play a significant role for electron heating, as impulsive and localized phenomena such as magnetic reconnection can efficiently transfer energy from the electromagnetic fields to particles.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Eruptive mass loss likely produces the energetic outbursts observed from some massive stars before they become core-collapse supernovae (SNe). The resulting dense circumstellar medium may also cause the subsequent SNe to be observed as Type IIn events. The leading hypothesis of the cause of these outbursts is the response of the envelope of the red supergiant (RSG) progenitor to energy deposition in the months to years prior to collapse. Early theoretical studies of this phenomenon were limited to 1D, leaving the 3D convective RSG structure unaddressed. Using <jats:monospace>FLASH</jats:monospace>'s hydrodynamic capabilities, we explore the 3D outcomes by constructing convective RSG envelope models and depositing energies less than the envelope binding energies on timescales shorter than the envelope dynamical time deep within them. We confirm the 1D prediction of an outward-moving acoustic pulse steepening into a shock, unbinding the outermost parts of the envelope. However, we find that the initial 2–4 km s<jats:sup>−1</jats:sup> convective motions seed the intrinsic convective instability associated with the high-entropy material deep in the envelope, enabling gas from deep within the envelope to escape and increasing the amount of ejected mass compared to an initially “quiescent” envelope. The 3D models reveal a rich density structure, with column densities varying by ≈10× along different lines of sight. Our work highlights that the 3D convective nature of RSG envelopes impacts our ability to reliably predict the outburst dynamics, the amount, and the spatial distribution of the ejected mass associated with deep energy deposition.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The canonical theory of star formation in a magnetized environment predicts the formation of hourglass-shaped magnetic fields during the prestellar collapse phase. In protostellar cores, recent observations reveal complex and strongly distorted magnetic fields in the inner regions that are sculpted by rotation and outflows. We conduct resistive, nonideal magnetohydrodynamic simulations of a protostellar core and employ the radiative transfer code POLARIS to produce synthetic polarization segment maps. A comparison of our mock-polarization maps based on the toroidal-dominated magnetic field in the outflow zone with the observed polarization vectors of SiO lines in Orion Source I shows a reasonable agreement when the magnetic axis is tilted at an angle <jats:italic>θ</jats:italic> = 15° with respect to the plane of the sky and if the SiO lines have a net polarization parallel to the local magnetic field. Although the observed polarization is from SiO lines and our synthetic maps are due to polarized dust emission, a comparison is useful and allows us to resolve the ambiguity of whether the line polarization is parallel or perpendicular to the local magnetic field direction.</jats:p>