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<jats:title>Abstract</jats:title> <jats:p>The kinematics and dynamics of stellar and substellar populations within young, still-forming clusters provide valuable information for constraining theories of formation mechanisms. Using Keck II NIRSPEC+AO data, we have measured radial velocities for 56 low-mass sources within 4′ of the core of the Orion Nebula Cluster (ONC). We also remeasure radial velocities for 172 sources observed with SDSS/APOGEE. These data are combined with proper motions measured using HST ACS/WFPC2/WFC3IR and Keck II NIRC2, creating a sample of 135 sources with all three velocity components. The velocities measured are consistent with a normal distribution in all three components. We measure intrinsic velocity dispersions of (<jats:inline-formula> <jats:tex-math> <?CDATA ${\sigma }_{{v}_{\alpha }}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>v</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3252ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math> <?CDATA ${\sigma }_{{v}_{\delta }}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>v</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>δ</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3252ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math> <?CDATA ${\sigma }_{{v}_{r}}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>v</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>r</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msub> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3252ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>) = (1.64 ± 0.12, 2.03 ± 0.13, <jats:inline-formula> <jats:tex-math> <?CDATA ${2.56}_{-0.17}^{+0.16}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>2.56</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.16</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3252ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>) km s<jats:sup>−1</jats:sup>. Our computed intrinsic velocity dispersion profiles are consistent with the dynamical equilibrium models from Da Rio et al. (2014) in the tangential direction but not in the line-of-sight direction, possibly indicating that the core of the ONC is not yet virialized, and may require a nonspherical potential to explain the observed velocity dispersion profiles. We also observe a slight elongation along the north–south direction following the filament, which has been well studied in previous literature, and an elongation in the line-of-sight to tangential velocity direction. These 3D kinematics will help in the development of realistic models of the formation and early evolution of massive clusters.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Jupiter’s enhancement in nitrogen relative to hydrogen when compared to the Sun has been interpreted as evidence that its early formation occurred beyond the N<jats:sub>2</jats:sub> snow line (∼20–40 au). However, the rapid growth necessary to form Jupiter before the dissipation of the solar nebula would lead to the forming planet’s core reaching very high temperatures (&gt;1000 K), which would lead to it warming its surroundings. Here, we explore the effects of a luminous planetary core on the solids that it ultimately accretes. We find that a critical transition occurs where very hot (rapidly accreting) cores drive off volatiles prior to accretion, while cool cores (slowly accreting) are able to inherit volatile rich solids. Given Jupiter’s nitrogen enrichment, if it formed beyond the N<jats:sub>2</jats:sub> snow line, its core could not have accreted solids at a rate above 10<jats:sup>−10</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>. Our results suggest that either Jupiter formed in more distal regions of the solar nebula, or nitrogen loss was suppressed, either by its incorporation in more refractory carriers or because it was trapped within ices that devolatilized at higher temperatures.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>ASASSN-14ko is a recently discovered periodically flaring transient at the center of the active galactic nucleus (AGN) ESO 253−G003 with a slowly decreasing period. Here, we show that the flares originate from the northern, brighter nucleus in this dual-AGN, post-merger system. The light curves for the two flares that occurred in 2020 May and September are nearly identical over all wavelengths. For both events, Swift observations showed that the UV and optical wavelengths brightened in unison. The effective temperature of the UV/optical emission rises and falls with the increase and subsequent decline in the luminosity. The X-ray flux, by contrast, first rapidly drops over ∼2.6 days, rises for ∼5.8 days, drops again over ∼4.3 days, and then recovers. The X-ray spectral evolution of the two flares differ, however. During the 2020 May peak the spectrum softened with increases in the X-ray luminosity, while we observed the reverse for the 2020 September peak. We found a small change in the period derivative, which seems to indicate that the system does not have a static period derivative and there is some stochasticity in its evolution.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>As a transient X-ray binary, MAXI J1659-152 contains a black hole candidate as its compact star. MAXI J1659-152 was discovered on 2010 September 25 during its only known outburst. Previously published studies of this outburst indicate that MAXI J1659-152 may have an extreme retrograde spin, which, if confirmed, would provide an important clue as to the origin of black hole spin. In this paper, utilizing updated dynamical binary system parameters (i.e., the black hole mass, the orbital inclination, and the source distance) provided by Torres et al., we analyze 65 spectra of MAXI J1659-152 from RXTE/PCA, in order to assess the spin parameter. With a final selection of nine spectra matching our <jats:italic>f</jats:italic> <jats:sub>sc</jats:sub> ≲ 25%, soft state criteria, we apply a relativistic thin disk spectroscopic model <jats:monospace>kerrbb2</jats:monospace> over 3.0–45.0 keV. We find that inclination angle correlates inversely with spin, and, considering the possible values for inclination angle, we constrain spin to be −1 &lt; <jats:italic>a</jats:italic> <jats:sub>*</jats:sub> ≲ 0.44 at a 90% confidence interval via X-ray continuum fitting. We can only rule out an extreme prograde (positive) spin. We confirm that an extreme retrograde solution is possible and is not ruled out by considering accretion torques given the young age of the system.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, we present multiwavelength observations of the triggering of a failed-eruptive M-class flare from active region NOAA 11302 and investigate the possible reasons for the associated failed eruption. Photospheric observations and nonlinear force-free field extrapolated coronal magnetic field revealed that the flaring region had a complex quadrupolar configuration with a preexisting coronal nullpoint situated above the core field. Prior to the onset of the M-class flare, we observed multiple periods of small-scale flux enhancements in GOES and RHESSI soft X-ray observations from the location of the nullpoint. The preflare configuration and evolution reported here are similar to the configurations presented in the breakout model, but at much lower coronal heights. The core of the flaring region was characterized by the presence of two flux ropes in a double-decker configuration. During the impulsive phase of the flare, one of the two flux ropes initially started erupting, but resulted in a failed eruption. Calculation of the magnetic decay index revealed a saddle-like profile where the decay index initially increased to the torus-unstable limits within the heights of the flux ropes, but then decreased rapidly and reached negative values, which was most likely responsible for the failed eruption of the initially torus-unstable flux rope.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Tidal disruption events (TDEs) occur when a star passes close enough to a galaxy’s supermassive black hole to be disrupted by tidal forces. We discuss new observations of IGRJ12580+0134, a TDE observed in NGC 4845 (<jats:italic>d</jats:italic> = 17 Mpc) in 2010 November, with the Karl G. Jansky Very Large Array (VLA<jats:xref ref-type="fn" rid="apjac3bbafn1"> <jats:sup>9</jats:sup> </jats:xref> <jats:fn id="apjac3bbafn1"> <jats:label> <jats:sup>9</jats:sup> </jats:label> <jats:p>The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.</jats:p> </jats:fn>). We also discuss a reanalysis of 2010–2011 Swift and XMM-Newton observations, as well as new, late-time Swift observations. Our JVLA observations show a decay of the nuclear radio flux until 2015, when a plateau was seen, and then a significant (factor ∼3) radio flare during 2016. The 2016 radio flare was also accompanied by radio spectral changes, but was not seen in the X-rays. We model the flare as resulting from the interaction of the nuclear jet with a cloud in the interstellar medium. This is distinct from late-time X-ray flares in a few other TDEs where changes in the accretion state and/or a fallback event were suggested, neither of which appears possible in this case. Our reanalysis of the Swift and XMM-Newton data from 2011 shows significant evidence for thermal emission from a disk, as well as a very soft power law. This, in addition to the extreme X-ray flux increase seen in 2010 (a factor of &gt;100) bolsters the identification of IGRJ12580+0134 as a TDE, not an unusual active galactic nucleus variability event.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Stellar abundances and ages afford the means to link chemical enrichment to galactic formation. In the Milky Way, individual element abundances show tight correlations with age, which vary in slope across ([Fe/H]–[<jats:italic>α</jats:italic>/Fe]). Here, we step from characterizing abundances as measures of age, to understanding how abundances trace properties of stellar birth environment in the disk over time. Using measurements from ∼27,000 APOGEE stars (<jats:italic>R</jats:italic> = 22,500, signal-to-noise ratio &gt; 200), we build simple local linear models to predict a sample of elements (X = Si, O, Ca, Ti, Ni, Al, Mn, Cr) using (Fe, Mg) abundances alone, as fiducial tracers of supernovae production channels. Given [Fe/H] and [Mg/H], we predict these elements, [X/H], to about double the uncertainty of their measurements. The intrinsic dispersion, after subtracting measurement errors in quadrature is ≈0.015–0.04 dex. The residuals of the prediction (measurement − model) for each element demonstrate that each element has an individual link to birth properties at fixed (Fe, Mg). Residuals from primarily massive-star supernovae (i.e., Si, O, Al) partially correlate with guiding radius. Residuals from primarily supernovae Ia (i.e., Mn, Ni) partially correlate with age. A fraction of the intrinsic scatter that persists at fixed (Fe, Mg), however, after accounting for correlations, does not appear to further discriminate between birth properties that can be traced with present-day measurements. Presumably, this is because the residuals are also, in part, a measure of the typical (in)-homogeneity of the disk’s stellar birth environments, previously inferred only using open cluster systems. Our study implies at fixed birth radius and time that there is a median scatter of ≈0.01–0.015 dex in elements generated in supernovae sources.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We have observed the 70 <jats:italic>μ</jats:italic>m dark infrared dark cloud (IRDC) G14.492-00.139 in the N<jats:sub>2</jats:sub>D<jats:sup>+</jats:sup> <jats:italic>J</jats:italic> = 3–2, DCO<jats:sup>+</jats:sup> <jats:italic>J</jats:italic> = 3–2, DCN <jats:italic>J</jats:italic> = 3–2, and C<jats:sup>18</jats:sup>O <jats:italic>J</jats:italic> = 2–1 lines, using the Atacama Large Millimeter/submillimeter Array (ALMA) as part of the ALMA Survey of 70 <jats:italic>μ</jats:italic>m Dark High-mass Clumps in Early Stages. We find that the spatial distribution is different among the observed emission from the deuterated molecular lines. The N<jats:sub>2</jats:sub>D<jats:sup>+</jats:sup> emission traces relatively quiescent regions, while both the DCO<jats:sup>+</jats:sup> and DCN emission emanate mainly from regions with signs of active star formation. In addition, the DCO<jats:sup>+</jats:sup>/N<jats:sub>2</jats:sub>D<jats:sup>+</jats:sup> ratio is found to be lower in several dense cores than in starless cores embedded in low-mass star-forming regions. By comparing the observational results with chemical-model calculations, we discuss the origin of the low DCO<jats:sup>+</jats:sup>/N<jats:sub>2</jats:sub>D<jats:sup>+</jats:sup> ratio in this IRDC clump. The low DCO<jats:sup>+</jats:sup>/N<jats:sub>2</jats:sub>D<jats:sup>+</jats:sup> ratio can be explained if the temperature of the dense cores is in the range between the sublimation temperatures of N<jats:sub>2</jats:sub> (∼20 K) and CO (∼25 K). The results suggest that the dense cores in G14.492-00.139 are warmer and denser than the dense cores in low-mass star-forming regions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigate the relationship between dust attenuation and stellar mass (<jats:italic>M</jats:italic> <jats:sub>*</jats:sub>) in star-forming galaxies over cosmic time. For this analysis, we compare measurements from the MOSFIRE Deep Evolution Field survey at <jats:italic>z</jats:italic> ∼ 2.3 and the Sloan Digital Sky Survey (SDSS) at <jats:italic>z </jats:italic>∼ 0, augmenting the latter optical data set with both UV Galaxy Evolution Explorer (GALEX) and mid-infrared Wide-field Infrared Survey Explorer (WISE) photometry from the GALEX-SDSS-WISE Catalog. We quantify dust attenuation using both spectroscopic measurements of H<jats:italic>α</jats:italic> and H<jats:italic>β</jats:italic> emission lines, and photometric measurements of the rest-UV stellar continuum. The H<jats:italic>α</jats:italic>/H<jats:italic>β</jats:italic> ratio is used to determine the magnitude of attenuation at the wavelength of H<jats:italic>α</jats:italic>, <jats:italic>A</jats:italic> <jats:sub>H<jats:italic>α</jats:italic> </jats:sub>. Rest-UV colors and spectral energy distribution fitting are used to estimate <jats:italic>A</jats:italic> <jats:sub>1600</jats:sub>, the magnitude of attenuation at a rest wavelength of 1600 Å. As in previous work, we find a lack of significant evolution in the relation between dust attenuation and <jats:italic>M</jats:italic> <jats:sub>*</jats:sub> over the redshift range <jats:italic>z </jats:italic>∼ 0 to <jats:italic>z </jats:italic>∼ 2.3. Folding in the latest estimates of the evolution of <jats:italic>M</jats:italic> <jats:sub>dust</jats:sub>, (<jats:italic>M</jats:italic> <jats:sub>dust</jats:sub>/<jats:italic>M</jats:italic> <jats:sub>gas</jats:sub>), and gas surface density at fixed <jats:italic>M</jats:italic> <jats:sub>*</jats:sub>, we find that the expected <jats:italic>M</jats:italic> <jats:sub>dust</jats:sub> and dust mass surface density are both significantly higher at <jats:italic>z </jats:italic>∼ 2.3 than at <jats:italic>z </jats:italic>∼ 0. These differences appear at odds with the lack of evolution in dust attenuation. To explain the striking constancy in attenuation versus <jats:italic>M</jats:italic> <jats:sub>*</jats:sub>, it is essential to determine the relationship between metallicity and (<jats:italic>M</jats:italic> <jats:sub>dust</jats:sub>/<jats:italic>M</jats:italic> <jats:sub>gas</jats:sub>), the dust mass absorption coefficient and dust geometry, and the evolution of these relations and quantities from <jats:italic>z </jats:italic>∼ 0 to <jats:italic>z </jats:italic>∼ 2.3.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Likelihood-free inference provides a rigorous approach to performing Bayesian analysis using forward simulations only. The main advantage of likelihood-free methods is their ability to account for complex physical processes and observational effects in forward simulations. Here we explore the potential of likelihood-free forward modeling for Bayesian cosmological inference using the redshift evolution of the cluster abundance combined with weak-lensing mass calibration. We use two complementary likelihood-free methods, namely Approximate Bayesian Computation (ABC) and Density-Estimation Likelihood-Free Inference (DELFI), to develop an analysis procedure for the inference of the cosmological parameters (Ω<jats:sub>m</jats:sub>, <jats:italic>σ</jats:italic> <jats:sub>8</jats:sub>) and the mass scale of the survey sample. Adopting an eROSITA-like selection function and a 10% scatter in the observable–mass relation in a flat ΛCDM cosmology with Ω<jats:sub>m</jats:sub> = 0.286 and <jats:italic>σ</jats:italic> <jats:sub>8</jats:sub> = 0.82, we create a synthetic catalog of observable-selected Navarro–Frenk–White clusters in a survey area of 50 deg<jats:sup>2</jats:sup>. The stacked tangential shear profile and the number counts in redshift bins are used as summary statistics for both methods. By performing a series of forward simulations, we obtain convergent solutions for the posterior distribution from both methods. We find that ABC recovers broader posteriors than DELFI, especially for the Ω<jats:sub>m</jats:sub> parameter. For a weak-lensing survey with a source density of <jats:italic>n</jats:italic> <jats:sub>g</jats:sub> = 20 arcmin<jats:sup>−2</jats:sup>, we obtain posterior constraints on <jats:inline-formula> <jats:tex-math> <?CDATA ${S}_{8}={\sigma }_{8}{\left({{\rm{\Omega }}}_{{\rm{m}}}/0.3\right)}^{0.3}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>S</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> </mml:msub> <mml:msup> <mml:mrow> <mml:mfenced close=")" open="("> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">Ω</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mn>0.3</mml:mn> </mml:mrow> </mml:mfenced> </mml:mrow> <mml:mrow> <mml:mn>0.3</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3d33ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> of 0.836 ± 0.032 and 0.810 ± 0.019 from ABC and DELFI, respectively. The analysis framework developed in this study will be particularly powerful for cosmological inference with ongoing cluster cosmology programs, such as the XMM–XXL survey and the eROSITA all-sky survey, in combination with wide-field weak-lensing surveys.</jats:p>