adsabs/AstroCLIMB huggingface dataset:
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Forward modeling of the LRS data to model and subtract the host starlight within the slit. Top two panels: the observed 2D dispersed spectral images for the two nod positions, oriented so that the LRS slit direction is vertical and the wavelength dispersion direction is horizontal. These contain both the spectral trace of GJ 229B and the dispersed PSF wings of the host star. Second two panels: forward model of the dispersed host star PSF wings for the two nod positions, generated using WebbPSF as discussed in the text. Third two panels: the observed data minus the PSF models. The contamination from the host star PSF wings is significantly reduced, though there are still smaller residuals due to model imperfections. Bottom panels: comparison of nod subtractions without and with the PSF subtraction. In the default subtraction, residual stellar speckles are visible between the two spectral traces, and indeed contaminating on top of those traces. With the star model subtraction, the clean speckle-free regions between the spectral traces show the reduction in contamination.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Histograms show the posteriors for C/O and [M/H] from our Sonora Elf Owl fits to Gliese 229Bab. The error bars show the measured abundances for Gliese 229A from the literature, whose sources are given in Section 4.4. The abundances of Bab and A are consistent at the <1σ level, demonstrating the power of JWST/MIRI LRS in making robust abundance measurements.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Top: the best-fit single brown dwarf model (red) and MIRI data (black) plotted with the corrected wavelength solution, ﹩\lambda ^{\prime} ﹩. The error bars are inflated by the best-fit error inflation term b from the model. Bottom: best-fit single model (blue) and MIRI data (black) plotted with the default wavelength values from the pipeline. The effect of the wavelength correction is most significant at wavelengths longward of 10 μm, which we show here.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Joint posterior distributions for ﹩\mathrm{log}g﹩, Teff, and radius of each brown dwarf from the binary model. The subscript 1 indicates the primary brown dwarf, Gliese 229Ba, and subscript 2 indicates Gliese 229Bb. The dashed lines on the 1D histograms show 95% confidence intervals, while dashed lines on the 2D histograms represent 1σ and 2σ contours.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Joint posterior distributions for C/O, [M/H], and ﹩\mathrm{log}{K}_{zz}﹩ for each brown dwarf from the binary model that assumes the same abundances for Ba and Bb. The dashed lines on the 1D histograms show 95% confidence intervals, while dashed lines on the 2D histograms represent 1σ and 2σ contours.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Two hundred random draws of Rλ = r0 + rλ from an initial single brown dwarf model.
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: The time evolution of downstream ion (left panel) and electron (right panel) temperatures in various simulations. The values are normalized with TMHD, which is computed using Equation (10) assuming a compression ratio of R = 4. Initially, when the compression is less than 4, the effective value of TMHD is larger than that used in the normalization. Consequently, the downstream temperatures of the ions might initially exceed TMHD used in the normalization. This is observed in the ﹩{{ \mathcal M }}_{{\rm{A}}}=21﹩ simulations for tωi < 15 × 103 (see bottom panels of Figure 1). This figure shows that using a reduced mass ratio leads to excessive heating for electrons at both low and high values of ﹩{{ \mathcal M }}_{{\rm{A}}}﹩. At ﹩{{ \mathcal M }}_{{\rm{A}}}=5.3﹩, this also results in lower heating in the downstream ions compared to the simulation with the same physical parameters and a realistic mass ratio. In all simulations, almost all the thermal energy is carried by ions (even if Te = Ti). Simulations with a realistic mass ratio convert about 78% of the upstream kinetic energy into thermal energy in the downstream region, primarily carried by ions. In contrast, simulations with a reduced mr recover this percentage only at high Alfvénic Mach numbers, and it is slightly lower (72%) at low Alfvénic Mach numbers, which dissipate more energy in magnetic fields, as seen in Figure 1.
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: The time evolution of the acceleration efficiency, i.e., the ability of various shocks to dissipate upstream kinetic energy into nonthermal ion (shown as dashed curves) and electron (shown as solid curves) energies. As shown in Figure 2, in the low ﹩{{ \mathcal M }}_{{\rm{A}}}﹩ simulation with the reduced mass ratio, electron acceleration is very inefficient. However, at the same ﹩{{ \mathcal M }}_{{\rm{A}}}﹩ with the realistic mass ratio, the efficiency is the highest among all simulations, including those with higher ﹩{{ \mathcal M }}_{{\rm{A}}}﹩. At higher ﹩{{ \mathcal M }}_{{\rm{A}}}﹩, the acceleration efficiency for electrons is systematically greater in the simulation with the reduced mass ratio. While the percentage of nonthermal energy in ions is approximately the same for both reduced and realistic mass ratios, the difference in how this energy is distributed at different momenta is manifested in the lower panels of Figure 2. In all simulations, about 11%–12% of the upstream kinetic energy is dissipated into nonthermal energy in ions, independent of the value of ﹩{{ \mathcal M }}_{{\rm{A}}}﹩. This is consistent with the hybrid simulations of D. Caprioli & A. Spitkovsky (2014). On the other hand, less than 1% is dissipated into nonthermal energy in electrons. This shows that the efficiency, especially that of electrons, evolves over time, contrary to what is incorrectly inferred from simulations run for much shorter physical times in the literature.
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: The time evolution of the ratio of downstream electron-to-ion temperatures in various simulations. In the case of a low Alfvénic Mach number (﹩{{ \mathcal M }}_{{\rm{A}}}=5.3﹩) with a reduced mass ratio (represented by the black curve), the high electron-to-ion temperature ratio is due to significantly less heating of ions, as shown in the left panel of Figure 4. At a high ﹩{{ \mathcal M }}_{{\rm{A}}}﹩ (﹩{{ \mathcal M }}_{{\rm{A}}}=21.3﹩), the ratio remains higher at the reduced mass ratio because of the significantly higher heating of electrons compared to the simulation with the same physical parameters but a realistic mass ratio. This figure highlights an important result for this work: the ion-to-electron temperature ratio is independent of the value of ﹩{{ \mathcal M }}_{{\rm{A}}}﹩ (or more precisely, independent of the upstream magnetic field value). This result cannot be deduced from simulations with a reduced mass ratio.
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: The time evolution of the maximum energy for ions and electrons normalized by their rest-mass energy, i.e., ﹩{\gamma }_{{\rm{\max }}}﹩, at the shock-front region, which is defined as a 400c/ωi region centered at the wave intensity jump locations shown in Figure 1. This shows that the maximum electron energy increases rapidly during shock formation in all simulations, with some simulations showing a slower increase or saturation afterward. For ions, the initial energy increase is slower than for electrons and appears consistent across simulations with the same Alfvénic Mach number, followed by slower growth with less oscillatory behavior.
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: XMM-Newton MOS light curve of EXO 0748–676 showing dips, eclipses, and a type I X-ray burst at MJD 60492.3097 (MET 836205954 s; see Section 3).
Paper: 131 and 304 Å Emission Variability Increases Hours Prior to Solar Flare Onset
Authors: Kara L. Kniezewski, E. I. Mason, Vadim M. Uritsky, Seth H. Garland
Figure caption: Example emission boxes for a M3.3 flare in 304 Å (top left), 171 Å (top right), 193 Å (bottom left), and 131 Å (bottom right). The boxes represent the emission integration region, which shares the same dimensions across each of the wavelength channels and remained constant throughout the 6 hr integration period.
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: (Top) The line significance is shown for the XMM-Newton RGS total spectrum. The horizontal dashed line shows a 2.8σ detection level above the continuum to account for the N VII line. (Bottom) The XMM-Newton RGS total spectrum with the line IDs for reference (see Appendix A).
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: Spectral fit of the total XMM-Newton MOS spectrum of EXO 0748–676 with a cutoffpl*pcfabs model. The spectral data (black) with the fit (yellow) overlaid (see Appendix B).
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: The XMM-Newton pn timing mode light curve of EXO 0748–676 is divided into three equal segments. In each segment, the evolution of the HR (top row), the soft (0.3–2 keV) light curve (middle row), and the hard (2–10 keV) light curve (bottom row) are shown. The eclipses are more prominent in the hard band but also detected in the soft band (see Appendix C).
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: Left: XMM-Newton OM fast mode light curve (blue) and MOS light curve (red) of EXO 0748–676. Both are binned at 2 s for visualization, and the vertical dashed line is placed at 836,205,958 s MET to mark the rise time of the X-ray burst. Right: cross-correlation plot between the X-ray and optical light curves. The vertical dashed line marks a 3 s lag of the optical burst with respect to the X-ray burst (see Appendix E).
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: XMM-Newton/RGS spectra for total observation, preburst, and postburst phases of EXO 0748–676. The O VII intercombination line is evident in all three phases. The broad Ne IX feature changes its ionization state from the preburst spectrum to the postburst spectrum (see Section 4).
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: (Left) CLOUDY model spectrum showing the expected lines. (Right) Model spectrum overlaid on the observed spectrum, showing the detected lines.
Paper: XMM-Newton High-resolution Spectroscopy of EXO 0748–676 after Its Reemergence from a Long Quiescence
Authors: Sayantan Bhattacharya, Sudip Bhattacharyya, Gargi Shaw
Figure caption: XMM-Newton/RGS spectra of dip (top) and nondip (bottom) phases of EXO 0748–676. This figure shows the effects of intensity dips on spectral lines (see Section 4.2).
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Top panel: MIRI LRS spectrum of Gliese 229Bab in black circles. The error bars shown have been inflated by the best-fit error inflation factor. The red dashed–dotted curve shows the best-fit model spectrum, which is the addition of the individual component spectra, Ba (purple), and Bb (teal). Bottom panel: residuals of the fit (data–model) plotted in units of σ differences. Overall, the data are well fit by the model (<2σ residuals), except for the wavelength region past 12 μm, where the pipeline calibration is still a work in progress.
Paper: Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Authors: Jerry W. Xuan, Marshall D. Perrin, Dimitri Mawet, Heather A. Knutson, Sagnick Mukherjee, Yapeng Zhang, Kielan K. W. Hoch, Jason J. Wang, Julie Inglis, Nicole L. Wallack, Jean-Baptiste Ruffio
Figure caption: Top panel: opacities of the major molecular absorbers in the mid-infrared spectrum of Gliese 229Bab. The units are cm2 molecule–1. Note that the y-axis is inverted. Bottom panel: MIRI LRS spectrum of Gliese 229Bab in black. The error bars are shown as shaded regions around the spectrum but are not visible by eye except for the reddest wavelengths.
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: Amplification and spatial structure of the perpendicular magnetic field component By in various simulations. The top panels show simulations with ﹩{{ \mathcal M }}_{{\rm{A}}}=5.1﹩, and the bottom panels show simulations with ﹩{{ \mathcal M }}_{{\rm{A}}}=21﹩. The left panels present simulations with a reduced ion-to-electron mass ratio mr = 100, while the right panels show simulations with the realistic mass ratio mr = 1836. The normalization is such that the square of this value represents the fraction of upstream shock kinetic energy density converted into the magnetic energy density of the By magnetic field component. In all cases, large-scale Alfvén waves are clearly generated near the shock front, with wavelengths approximately given by ﹩\lambda \unicode{x0007E}2\pi {{ \mathcal M }}_{{\rm{A}}}c/{\omega }_{i}﹩, which is consistent with the scale expected from a streaming instability gyroscale wave mode driven by the incoming upstream cold plasma penetrating through the downstream denser electron–ion plasma (see Section 3). The region to the left of the white lines indicates what we refer to as the downstream region of the shock, which is approximately 200c/ωi away from the shock front, evidenced by a clear transition in the field amplitude in all panels. This shows that in all simulations, roughly 10% of the upstream plasma kinetic energy is converted into magnetic field energy, seemingly independent of the far-upstream magnetic energy density.
Paper: A New View of the Spiral Structure of the Northern Outer Milky Way in Carbon Monoxide
Authors: Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang, Min Wang
Figure caption: (a) Distribution of MCs projected into the Galactic plane. Each circle represents a single cloud with size scaled by cloud mass. The solid lines trace the log-periodic spiral fitting results to MCs weighted by mass. (b) Surface molecular gas density distribution map. Each MC was brightened with a Gaussian function. To highlight the main structure, the intensity is normalized to unity. Galactic quadrants are marked. (c) Same as panel (b) but with cloud masses corrected for variations in XCO and sensitivity clip factors. (d) Comparison between CO and other tracers. Dashed lines are the models on the basis of selected HMSFRs in the Outer and Perseus arms (M. J. Reid et al. 2019). Red dotted–dashed lines represent the H I arm models (E. S. Levine et al. 2006). Pink circles indicate the classical Cepheid variable stars (D. M. Skowron et al. 2019).
Paper: Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations
Authors: Mohamad Shalaby
Figure caption: The time evolution of particle spectra (solid lines: electrons; dashed lines: ions) at the downstream region defined as the region to the left of white curved in Figure 1. All spectra are computed from particle momenta in the contact-discontinuity (simulation) frame. The momentum is normalized to the upstream kinetic energy in the shock rest frame, with vsh computed from Equation (1) assuming a compression ratio of R = 4. The top-right panels show results from the simulation that can destabilize intermediate-scale unstable wave modes. The vertical blue line indicates the particle momenta for which the particle gyroradius is in resonance with the fastest-growing modes (Equation (9)). At a low Alfvénic Mach number ﹩{{ \mathcal M }}_{{\rm{A}}}=5.3﹩, the reduced mass ratio leads to complete suppression of electron acceleration, while very efficient electron acceleration is observed with the realistic mass ratio, enabling destabilization of the intermediate-scale instability. Ion acceleration, however, is similar in both simulations. At a high Alfvénic Mach number ﹩{{ \mathcal M }}_{{\rm{A}}}=21.3﹩, the reduced mass ratio results in much more efficient electron acceleration compared to the simulation with the realistic mass ratio, indicating that the mechanism for such acceleration is also sensitive to the mass ratio. This sensitivity is also observed in ion acceleration, where the reduced mass ratio leads to an nonphysically high flux of ions at high momentum compared to the simulation with the realistic mass ratio.
Paper: A New View of the Spiral Structure of the Northern Outer Milky Way in Carbon Monoxide
Authors: Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang, Min Wang
Figure caption: MCs and HMSFRs at the Galactic outskirts. The available distant MCs are superposed on the new view of the Milky Way based on 200 trigonometric parallaxes for masers in HMSFRs (credit: Xing-Wu Zheng & Mark Reid BeSSeL/NJU/CfA). The 1306 MCs from this study and 10 MCs from the literature (T. M. Dame & P. Thaddeus 2011) are indicated by cyan and red circles, respectively. The two symmetrical spirals and their extensions, namely, the Scutum–Centaurus and Perseus arms, are indicated by two logarithmic spirals with a pitch angle of 12∘ averaged over various tracers (J. P. Vallée 2008). The solid logarithmic spiral indicates the fit for the OSC arm (CO model 2b). The cyan square denotes the HMSFR of the OSC arm with a trigonometric parallax measurement (A. Sanna et al. 2017). The diamond marks the location of the HMSFR calculated by the kinematic method. The yellow pluses and crosses indicate the distant H II regions (L. D. Anderson et al. 2012, 2015; W. P. Armentrout et al. 2017) and star-forming masers (W. P. Armentrout et al. 2017; Y. Sun et al. 2018b), respectively.
Paper: A New View of the Spiral Structure of the Northern Outer Milky Way in Carbon Monoxide
Authors: Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang, Min Wang
Figure caption: (a) MC distribution in the l-vlsr map. The total numbers of MCs in each spiral arm are indicated in the corner. The size of individual circles gives an indication of cloud mass. The smallest circle is related to MCs with a mass less than 100 M⊙, while the largest circle corresponds to those with a mass greater than 106 M⊙. The gray and color-coded lines represent the spiral arm loci from M. J. Reid et al. (2019) and MCs in this study. (b) Histograms illustrate the mass distributions of each spiral arm along the Galactic longitude in each 5∘ bin. (c) Distribution of MCs in the Galactic coordinates (l, b). The HMSFRs of the Perseus and Outer arm segments are indicated by open circles and filled squares, respectively (M. J. Reid et al. 2019).
Paper: A New View of the Spiral Structure of the Northern Outer Milky Way in Carbon Monoxide
Authors: Yan Sun, Ji Yang, Shaobo Zhang, Qing-Zeng Yan, Yang Su, Xuepeng Chen, Xin Zhou, Ye Xu, Hongchi Wang, Min Wang, Zhibo Jiang, Ji-Xian Sun, Deng-Rong Lu, Bing-Gang Ju, Xu-Guo Zhang, Min Wang
Figure caption: An example of MCs probably lying along the new extension of the OSC arm in the third quadrant. The blue stars indicate the center of the cloud. The white contours indicate the boundary of the cloud in the l-b-v intensity maps. The CO and H I spectra show emission at the CO emission peak and emission averaged over the white boundary.