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<jats:title>Abstract</jats:title> <jats:p>Type II radio bursts are thought to be produced by shock waves in the solar atmosphere. However, what magnetic conditions are needed for the generation of type II radio bursts is still a puzzling issue. Here, we quantify the magnetic structure of a coronal shock associated with a type II radio burst. Based on multiperspective extreme-ultraviolet observations, we reconstruct the three-dimensional (3D) shock surface. By using a magnetic field extrapolation model, we then derive the orientation of the magnetic field relative to the normal of the shock front (<jats:italic>θ</jats:italic> <jats:sub>Bn</jats:sub>) and the Alfvén Mach number (<jats:italic>M</jats:italic> <jats:sub> <jats:italic>A</jats:italic> </jats:sub>) on the shock front. Combining the radio observations from the Nancay Radio Heliograph, we obtain the source region of the type II radio burst on the shock front. It is found that the radio burst is generated by a shock with <jats:italic>M</jats:italic> <jats:sub> <jats:italic>A</jats:italic> </jats:sub> ≳ 1.5 and a bimodal distribution of <jats:italic>θ</jats:italic> <jats:sub>Bn</jats:sub>. We also use the Rankine–Hugoniot relations to quantify the properties of the shock downstream. Our results provide a quantitative 3D magnetic structure condition of a coronal shock that produces a type II radio burst.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigated the chemical evolutions of gas-phase and grain-surface species across the Taurus molecular cloud-1 (TMC-1) filament from the translucent phase to the dense phase. By comparing observations with modeling results from an up-to-date chemical network, we examined the conversion processes for the carbon-, oxygen-, nitrogen-, and sulfur-bearing species, i.e., from their initial atomic form to their main molecular reservoir form both in the gas phase and on the grain surface. The conversion processes were found to depend on the species and <jats:italic>A</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub>. The effect of initial carbon-to-oxygen elemental abundances ratio (C/O) by varying O on the chemistry was explored, and an initial carbon elemental abundance of 2.5 × 10<jats:sup>−4</jats:sup> and a C/O ratio of 0.5 could best reproduce the abundances of most observed molecules at TMC-1 CP, where more than 90 molecules have been identified. Based on the TMC-1 condition, we predicted a varied grain ice composition during the evolutions of molecular clouds, with H<jats:sub>2</jats:sub>O ice as the dominant ice composition at <jats:italic>A</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> &gt; 4 mag, CO<jats:sub>2</jats:sub> ice as the dominant ice composition at <jats:italic>A</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> &lt;4 mag, while CO ice severely decreased at <jats:italic>A</jats:italic> <jats:sub> <jats:italic>V</jats:italic> </jats:sub> around 4–5 mag.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Gas-phase and solid-state chemistry in low-temperature interstellar clouds and cores leads to a D/H enhancement in interstellar ices, which is eventually inherited by comets, meteorites, and even planetary satellites. Hence, the D/H ratio has been widely used as a tracer for the origins of extraterrestrial chemistry. However, the D/H ratio can also be influenced by cosmic rays, which are ubiquitous and can penetrate even dense interstellar molecular cores. The effects of such high-energy radiation on deuterium fractionation have not been studied in a quantitative manner. In this study, we present rate constants for radiation-induced D-to-H exchange for fully deuterated small (1–2 C) hydrocarbons embedded in H<jats:sub>2</jats:sub>O ice at 20 K and H-to-D exchange for the protiated forms of these molecules in D<jats:sub>2</jats:sub>O ice at 20 K. We observed larger rate constants for H-to-D exchange in the D<jats:sub>2</jats:sub>O ice versus D-to-H exchange in H<jats:sub>2</jats:sub>O ice, which we have attributed to the greater bond strength of C–D versus C–H. We find that the H-to-D exchange rate constants are smaller for protiated methane than ethane, in agreement with bond energies from the literature. We are unable to obtain rate constants for the unsaturated and reactive hydrocarbons ethylene and acetylene. Interpretation of the rate constants suggest that D/H exchange products are formed in abundance alongside radiolysis products. We discuss how our quantitative and qualitative data can be used to interpret the D/H ratios of aliphatic compounds observed throughout space.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Zank et al. developed models describing the transport of low-frequency incompressible and nearly incompressible turbulence in inhomogeneous flows. The formalism was based on expressing the fluctuating variables in terms of the Elsässar variables and then taking “moments” subject to various closure hypotheses. The turbulence transport models are different according to whether the plasma beta regime is large, of order unity, or small. Here, we show explicitly that the three sets of turbulence transport models admit a conservation representation that resembles the well-known WKB transport equation for Alfvén wave energy density after introducing appropriate definitions of the “pressure” associated with the turbulent fluctuations. This includes introducing a distinct turbulent pressure tensor for 3D incompressible turbulence (the large plasma beta limit) and pressure tensors for quasi-2D and slab turbulence (the plasma beta order-unity or small regimes) that generalize the form of the WKB pressure tensor. Various limits of the different turbulent pressure tensors are discussed. However, the analogy between the conservation form of the turbulence transport models and the WKB model is not close for multiple reasons, including that the turbulence models express fully nonlinear physical processes unlike the strictly linear WKB description. The analysis presented here both serves as a check on the validity and correctness of the turbulence transport models and also provides greater transparency of the energy dissipation term and the “turbulent pressure” in our models, which is important for many practical applications.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present the public release of the Complete History of Interaction-Powered Supernovae (CHIPS) code, which is suited to model a variety of transients that arise from interaction with a dense circumstellar medium (CSM). Contrary to existing modelings, which mostly attach the CSM by hand, CHIPS self-consistently simulates both the creation of the CSM from mass eruption of massive stars prior to core collapse, and the subsequent supernova light curve. We demonstrate the performance of CHIPS by presenting examples of the density profiles of the CSM and the light curves. We show that the gross light-curve properties of putative interaction-powered transients (e.g., Type IIn supernovae, rapidly evolving transients and recently discovered fast blue optical transients) can be comprehensively explained with the output of CHIPS.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We perform a profile analysis of the combined H <jats:sc>i</jats:sc> data cube of the Large Magellanic Cloud (LMC) from observations with the Australia Telescope Compact Array and the Parkes radio telescope. For the profile analysis, we use a newly developed algorithm that decomposes individual line profiles into an optimal number of Gaussian components based on a Bayesian nested sampling. The decomposed Gaussian components are then classified into <jats:italic>kinematically</jats:italic> cold, warm, and hot gas components based on their velocity dispersion. The estimated masses of the kinematically cold, warm, and hot gas components are ∼12.2%, ∼58.3%, and ∼29.5% of the total H <jats:sc>i</jats:sc> mass of the LMC, respectively. Our analysis reveals the highly complex H <jats:sc>i</jats:sc> structure and kinematics of the LMC that are seen in previous studies but in a more quantitative manner. We also extract the undisturbed H <jats:sc>i</jats:sc> gas bulk motions and derive new H <jats:sc>i</jats:sc> gas bulk rotation curves of the LMC by applying a 2D tilted-ring analysis. In contrast to previously derived H <jats:sc>i</jats:sc> rotation curves, the newly derived bulk rotation curves are much more consistent with the carbon star kinematics, with rotation velocity linearly increasing in the inner part and reaching a maximum of ∼60 km s<jats:sup>−1</jats:sup> at the outermost measured radius. By comparing the lower bulk rotation curves with previous studies, we conclude that there is a lower dynamical contribution of dark matter in the central part of the LMC.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Mid-infrared (MIR) images of the Galactic center show extended gas and dust features along with bright infrared sources (IRS). Some of these dust features are a part of ionized clumpy streamers orbiting Sgr A*, known as the mini-spiral. We present their proper motions over a 12 yr time period and report their flux densities in <jats:italic>N</jats:italic>-band filters and derive their spectral indices. The observations were carried out by VISIR at the ESO’s Very Large Telescope. High-pass filtering led to the detection of several resolved filaments and clumps along the mini-spiral. Each source was fit by a 2D Gaussian profile to determine the offsets and aperture sizes. We perform aperture photometry to extract fluxes in two different bands. We present the proper motions of the largest consistent set of resolved and reliably determined sources. In addition to stellar orbital motions, we identify a stream-like motion of extended clumps along the mini-spiral. We also detect MIR counterparts of the radio tail components of the IRS 7 source. They show a clear kinematical deviation with respect to the star. They likely represent Kelvin–Helmholtz instabilities formed downstream in the shocked stellar wind. We also analyze the shape and orientation of the extended late-type IRS 3 star that is consistent with the Atacama Large Millimeter/submillimeter Array submillimeter detection of the source. Its puffed-up envelope with a radius of ∼2 × 10<jats:sup>6</jats:sup> <jats:italic>R</jats:italic> <jats:sub>⊙</jats:sub> could be the result of the red-giant collision with a nuclear jet, which was followed by tidal prolongation along the orbit.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a stellar dynamical mass measurement of a newly detected supermassive black hole (SMBH) at the center of the fast-rotating, massive elliptical galaxy NGC 2693 as part of the MASSIVE survey. We combine high signal-to-noise ratio integral field spectroscopy (IFS) from the Gemini Multi-Object Spectrograph with wide-field data from the Mitchell Spectrograph at McDonald Observatory to extract and model stellar kinematics of NGC 2693 from the central ∼150 pc out to ∼2.5 effective radii. Observations from Hubble Space Telescope WFC3 are used to determine the stellar light distribution. We perform fully triaxial Schwarzschild orbit modeling using the latest TriOS code and a Bayesian search in 6D galaxy model parameter space to determine NGC 2693's SMBH mass (<jats:italic>M</jats:italic> <jats:sub>BH</jats:sub>), stellar mass-to-light ratio, dark matter content, and intrinsic shape. We find <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\mathrm{BH}}=\left(1.7\pm 0.4\right)\times {10}^{9}\ {M}_{\odot }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mn>1.7</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.4</mml:mn> </mml:mrow> </mml:mfenced> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.33em" /> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac58fdieqn1.gif" xlink:type="simple" /> </jats:inline-formula> and a triaxial intrinsic shape with axis ratios <jats:italic>p</jats:italic> = <jats:italic>b</jats:italic>/<jats:italic>a</jats:italic> = 0.902 ± 0.009 and <jats:inline-formula> <jats:tex-math> <?CDATA $q=c/a={0.721}_{-0.010}^{+0.011}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>q</mml:mi> <mml:mo>=</mml:mo> <mml:mi>c</mml:mi> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mi>a</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>0.721</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.010</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.011</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac58fdieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, triaxiality parameter <jats:italic>T</jats:italic> = 0.39 ± 0.04. In comparison, the best-fit orbit model in the axisymmetric limit and (cylindrical) Jeans anisotropic model of NGC 2693 prefer <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\mathrm{BH}}=\left(2.4\pm 0.6\right)\times {10}^{9}\ {M}_{\odot }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mn>2.4</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.6</mml:mn> </mml:mrow> </mml:mfenced> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.33em" /> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac58fdieqn3.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\mathrm{BH}}=\left(2.9\pm 0.3\right)\times {10}^{9}\ {M}_{\odot }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BH</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mn>2.9</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.3</mml:mn> </mml:mrow> </mml:mfenced> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>9</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.33em" /> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac58fdieqn4.gif" xlink:type="simple" /> </jats:inline-formula>, respectively. Neither model can account for the non-axisymmetric stellar velocity features present in the IFS data.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We report the detection of a strong thermal component in the short gamma-ray burst 170206A with three intense pulses in its light curves, throughout which the fluxes of this thermal component exhibit fast temporal variability the same as that of the accompanying nonthermal component. The values of the time-resolved low-energy photon index in the nonthermal component are between about −0.79 and −0.16, most of which are harder than the −2/3 expected in the synchrotron emission process. In addition, we found a common evolution between the thermal component and the nonthermal component, <jats:inline-formula> <jats:tex-math> <?CDATA ${E}_{{\rm{p}},\mathrm{CPL}}\propto {{kT}}_{\mathrm{BB}}^{0.95\pm 0.28}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">p</mml:mi> <mml:mo>,</mml:mo> <mml:mi>CPL</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∝</mml:mo> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="italic">kT</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BB</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0.95</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.28</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac6176ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> <?CDATA ${F}_{\mathrm{CPL}}\propto {F}_{\mathrm{BB}}^{0.67\pm 0.18}$?> </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:mi>CPL</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∝</mml:mo> <mml:msubsup> <mml:mrow> <mml:mi>F</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>BB</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>0.67</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.18</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac6176ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, where <jats:italic>E</jats:italic> <jats:sub>p,CPL</jats:sub> and <jats:italic>F</jats:italic> <jats:sub>CPL</jats:sub> are the peak photon energy and corresponding flux of the nonthermal component, and <jats:italic>kT</jats:italic> <jats:sub>BB</jats:sub> and <jats:italic>F</jats:italic> <jats:sub>BB</jats:sub> are the temperature and corresponding flux of the thermal component, respectively. Finally, we proposed that the photospheric thermal emission and the Comptonization of thermal photons may be responsible for the observational features of GRB 170206A.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>With Σ<jats:sub>SFR</jats:sub> ∼ 4200 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup> kpc<jats:sup>−2</jats:sup>, SPT 0346–52 (<jats:italic>z</jats:italic> = 5.7) is the most intensely star-forming galaxy discovered by the South Pole Telescope. In this paper, we expand on previous spatially resolved studies, using ALMA observations of dust continuum, [N <jats:sc>ii</jats:sc>] 205 <jats:italic>μ</jats:italic>m, [C <jats:sc>ii</jats:sc>] 158 <jats:italic>μ</jats:italic>m, [O <jats:sc>i</jats:sc>] 146 <jats:italic>μ</jats:italic>m, and undetected [N <jats:sc>ii</jats:sc>] 122 <jats:italic>μ</jats:italic>m and [O <jats:sc>i</jats:sc>] 63 <jats:italic>μ</jats:italic>m emission to study the multiphase interstellar medium (ISM) in SPT 0346–52. We use pixelated, visibility-based lens modeling to reconstruct the source-plane emission. We also model the source-plane emission using the photoionization code <jats:sc>cloudy</jats:sc> and find a supersolar metallicity system. We calculate <jats:italic>T</jats:italic> <jats:sub>dust</jats:sub> = 48.3 K and <jats:italic>λ</jats:italic> <jats:sub>peak</jats:sub> = 80 <jats:italic>μ</jats:italic>m and see line deficits in all five lines. The ionized gas is less dense than comparable galaxies, with <jats:italic>n</jats:italic> <jats:sub> <jats:italic>e</jats:italic> </jats:sub> &lt; 32 cm<jats:sup>−3</jats:sup>, while ∼20% of the [C <jats:sc>ii</jats:sc>] 158 <jats:italic>μ</jats:italic>m emission originates from the ionized phase of the ISM. We also calculate the masses of several phases of the ISM. We find that molecular gas dominates the mass of the ISM in SPT 0346–52, with the molecular gas mass ∼4× higher than the neutral atomic gas mass and ∼100× higher than the ionized gas mass.</jats:p>