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  • The Cosmic Merger Rate Density Evolution of Compact Binaries Formed in Young Star Clusters and in Isolated Binaries
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Filippo Santoliquido, Michela Mapelli, Yann Bouffanais, Nicola Giacobbo, Ugo N. Di Carlo, Sara Rastello, M. Celeste Artale, and Alessandro Ballone

    Next generation ground-based gravitational-wave detectors will observe binary black hole (BBH) mergers up to redshift ##IMG## [http://ej.iop.org/images/0004-637X/898/2/152/apjab9b78ieqn1.gif] {$z\gtrsim 10$} , probing the evolution of compact binary (CB) mergers across cosmic time. Here, we present a new data-driven model to estimate the cosmic merger rate density (MRD) evolution of CBs, by coupling

    更新日期:2020-08-03
  • The R -Process Alliance: First Magellan/MIKE Release from the Southern Search for R -process-enhanced Stars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Rana Ezzeddine, Kaitlin Rasmussen, Anna Frebel, Anirudh Chiti, Karina Hinojisa, Vinicius M. Placco, Alexander P. Ji, Timothy C. Beers, Terese T. Hansen, Ian U. Roederer, Charli M. Sakari, and Jorge Melendez

    Extensive progress has recently been made in our understanding of heavy-element production via the r -process in the universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational-wave signal detected by LIGO, GW170817. The chemical abundance patterns of metal-poor r -process-enhanced stars provide key evidence for the dominant site(s) of the

    更新日期:2020-08-03
  • How Do Supernovae Impact the Circumgalactic Medium? I. Large-scale Fountains around a Milky Way–like Galaxy
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Miao Li and Stephanie Tonnesen

    Feedback is indispensable in galaxy formation. However, lacking resolutions, cosmological simulations often use ad hoc feedback parameters. Conversely, small-box simulations, while they better resolve the feedback, cannot capture gas evolution beyond the simulation domain. We aim to bridge the gap by implementing small-box results of supernovae-driven outflows into dark matter halo-scale simulations

    更新日期:2020-08-03
  • Dust Populations in the Iconic Vega Planetary System Resolved by ALMA
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Luca Matrà, William R. F. Dent, David J. Wilner, Sebastián Marino, Mark C. Wyatt, Jonathan P. Marshall, Kate Y. L. Su, Miguel Chavez, Antonio Hales, A. Meredith Hughes, Jane S. Greaves, and Stuartt A. Corder

    The Vega planetary system hosts the archetype of extrasolar Kuiper belts and is rich in dust from the sub-astronomical unit region out to hundreds of astronomical units, suggesting intense dynamical activity. We present Atacama Large Millimeter/submillimeter Array (ALMA) millimeter observations that detect and resolve the outer dust belt from the star for the first time. The interferometric visibilities

    更新日期:2020-08-03
  • The Massive and Distant Clusters of WISE Survey. IX. High Radio Activity in a Merging Cluster
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Emily Moravec, Anthony H. Gonzalez, Simon Dicker, Stacey Alberts, Mark Brodwin, Tracy E. Clarke, Thomas Connor, Bandon Decker, Mark Devlin, Peter R. M. Eisenhardt, Brian S. Mason, Wenli Mo, Tony Mroczkowski, Alexandra Pope, Charles E. Romero, Craig Sarazin, Jonathan Sievers, Spencer A. Stanford, Daniel Stern, Dominika Wylezalek, and Fernando Zago

    We present a multiwavelength investigation of the radio galaxy population in the galaxy cluster MOO J1506+5137 at z = 1.09 ± 0.03, which in previous work we identified as having multiple complex radio sources. The combined data set used in this work includes data from the Low-Frequency Array Two-meter Sky Survey, NSF’s Karl G. Jansky Very Large Array, the Robert C. Byrd Green Bank Telescope, the Spitzer

    更新日期:2020-08-03
  • Hydrodynamic Response of the Intergalactic Medium to Reionization
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Anson D’Aloisio, Matthew McQuinn, Hy Trac, Christopher Cain, and Andrei Mesinger

    The intergalactic medium is expected to clump on scales down to ##IMG## [http://ej.iop.org/images/0004-637X/898/2/149/apjab9f2fieqn1.gif] {${10}^{4}\mbox{--}{10}^{8}$} M ⊙ before the onset of reionization. The impact of these small-scale structures on reionization is poorly understood despite the modern understanding that gas clumpiness limits the growth of ##IMG## [http://ej.iop.org/images/0004-6

    更新日期:2020-08-03
  • Molecular Gas in 21 and 30 μ m Sources: The 2 mm and 1.3 mm Spectra of IRAS 21318+5631 and 22272+5435
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Yong Zhang

    The carriers of the 21 and 30 μ m emission features in infrared spectra of circumstellar envelopes are a long-standing enigma. In this paper, we present the results of molecular line observations toward two circumstellar envelopes exhibiting the 21 and/or 30 μ m features, IRAS 21318+5631 and 22272+5435. We investigate whether they have unusual gas-phase chemistry and search for a possible gas-phase

    更新日期:2020-08-03
  • Gaia and Hubble Unveil the Kinematics of Stellar Populations in the Type II Globular Clusters ω Centauri and M22
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    G. Cordoni, A. P. Milone, A. F. Marino, G. S. Da Costa, E. Dondoglio, H. Jerjen, E. P. Lagioia, A. Mastrobuono-Battisti, J. E. Norris, M. Tailo, and D. Yong

    The origin of multiple stellar populations in globular clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N -body simulations suggest that the present-day dynamics of GC stars can constrain the events that occurred at high redshift and led to the formation of multiple populations. Here, we combine multiband photometry from the Hubble Space Telescope (HST) and ground-based

    更新日期:2020-08-03
  • Population Synthesis of Black Hole X-Ray Binaries
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Yong Shao and Xiang-Dong Li

    We present a systematic study of the X-ray binaries (XRBs) containing a black hole (BH) and a nondegenerate companion, in which mass transfer takes place via either capturing the companion’s wind or Roche lobe overflow (RLO). As shown in our previous work, which focused on the formation and evolution of detached BH binaries, our assumed models relevant to BHs’ progenitors predicted significantly different

    更新日期:2020-08-03
  • High-resolution Spectroscopy of an Erupting Minifilament and Its Impact on the Nearby Chromosphere
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    I. Kontogiannis, E. Dineva, A. Diercke, M. Verma, C. Kuckein, H. Balthasar, and C. Denker

    We study the evolution of a minifilament eruption in a quiet region at the center of the solar disk and its impact on the ambient atmosphere. We used high spectral resolution imaging spectroscopy in H α acquired by the echelle spectrograph of the Vacuum Tower Telescope, Tenerife, Spain; photospheric magnetic field observations from the Helioseismic Magnetic Imager; and UV/EUV imaging from the Atmospheric

    更新日期:2020-08-03
  • Extremely Metal-poor Representatives Explored by the Subaru Survey (EMPRESS). I. A Successful Machine-learning Selection of Metal-poor Galaxies and the Discovery of a Galaxy with M * < 10 6 M ⊙ and 0.016 Z ⊙
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Takashi Kojima, Masami Ouchi, Michael Rauch, Yoshiaki Ono, Kimihiko Nakajima, Yuki Isobe, Seiji Fujimoto, Yuichi Harikane, Takuya Hashimoto, Masao Hayashi, Yutaka Komiyama, Haruka Kusakabe, Ji Hoon Kim, Chien-Hsiu Lee, Shiro Mukae, Tohru Nagao, Masato Onodera, Takatoshi Shibuya, Yuma Sugahara, Masayuki Umemura, and Kiyoto Yabe

    We have initiated a new survey for local extremely metal-poor galaxies (EMPGs) with Subaru/Hyper Suprime-Cam (HSC) large-area (∼500 deg 2 ) optical images reaching a 5 σ limit of ∼26 mag, about 100 times deeper than the Sloan Digital Sky Survey (SDSS). To select Z / Z ⊙ < 0.1 EMPGs from ∼40 million sources detected in the Subaru images, we first develop a machine-learning (ML) classifier based on a

    更新日期:2020-08-03
  • Large-scale CO Spiral Arms and Complex Kinematics Associated with the T Tauri Star RU Lup
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    Jane Huang, Sean M. Andrews, Karin I. Öberg, Megan Ansdell, Myriam Benisty, John M. Carpenter, Andrea Isella, Laura M. Pérez, Luca Ricci, Jonathan P. Williams, David J. Wilner, and Zhaohuan Zhu

    While protoplanetary disks often appear to be compact and well organized in millimeter continuum emission, CO spectral line observations are increasingly revealing complex behavior at large distances from the host star. We present deep Atacama Large Millimeter/submillimeter Array maps of the J = 2−1 transition of 12 CO, 13 CO, and C 18 O, as well as the J = 3−2 transition of DCO + , toward the T Tauri

    更新日期:2020-08-03
  • Space Telescope and Optical Reverberation Mapping Project. XI. Disk-wind Characteristics and Contributions to the Very Broad Emission Lines of NGC 5548
    Astrophys. J.  (IF 5.745) Pub Date : 2020-08-02
    M. Dehghanian, G. J. Ferland, G. A. Kriss, B. M. Peterson, K. T. Korista, M. R. Goad, M. Chatzikos, F. Guzmán, G. De Rosa, M. Mehdipour, J. Kaastra, S. Mathur, M. Vestergaard, D. Proga, T. Waters, M. C. Bentz, S. Bisogni, W. N. Brandt, E. Dalla Bontà, M. M. Fausnaugh, J. M. Gelbord, Keith Horne, I. M. McHardy, R. W. Pogge, and D. A. Starkey

    In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper

    更新日期:2020-08-03
  • The Decaying and Scattering Properties of the d *(2380) Hexaquark Bose–Einstein Condensate Dark Matter
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Man Ho Chan

    Recently, a study has shown that the Bose–Einstein condensates (BECs) formed by the d *(2380) hexaquarks ( d *(2380)-BECs) can be thermally produced in the early universe and they are stable enough to be a competitive candidate for dark matter. Searching for the decaying signature of d *(2380)-BECs is a possible way to verify this dark matter model. In this article, we discuss the scattering and decaying

    更新日期:2020-07-31
  • Synchrotron Self-Compton Scattering in Sgr A* Derived from NIR and X-Ray Flare Statistics
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Matthias Subroweit, Enmanuelle Mossoux, and Andreas Eckart

    The flaring activity of Sagittarius A* (Sgr A*) can be analyzed by statistical means to test emission models for its accretion flow. A particular modeling question is whether the observed X-ray flares are the high-energy end of a synchrotron spectrum or if they arise from self-Comptonized photons of a lower-energy synchrotron process. We use already published Chandra X-ray Visionary Project data to

    更新日期:2020-07-31
  • Heuristic Description of Perpendicular Particle Transport in Turbulence with Super-diffusive Magnetic Field Lines
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    A. Shalchi

    Recently a heuristic description of collisionless perpendicular diffusion of energetic particles was presented. The latter approach describes the transport of energetic particles across a mean magnetic field based on simple physical arguments. Although this approach was developed with the intention to improve our understanding of perpendicular diffusion, this heuristic approach also provided some interesting

    更新日期:2020-07-31
  • KIC 12268220: A δ Scuti Pulsating Star and an Active Protohelium White Dwarf in an Eclipsing Binary System
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Kaiming Cui, Zhao Guo, Qing Gao, Juanjuan Ren, Junbo Zhang, Yutao Zhou, and Jifeng Liu

    We present a photometric, spectroscopic, asteroseismic, and evolutionary analysis of the Algol-type eclipsing binary KIC 12268220. We find the O’Connell effect and anticorrelated eclipse timing variations in the Kepler light curve, revealing the presence of large starspots. Radial velocities and atmospheric parameters are obtained from ground-based spectroscopic observations. Combined with the radial

    更新日期:2020-07-31
  • Semianalytic Expressions for the Isolation and Coupling of Mixed Modes
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    J. M. Joel Ong and Sarbani Basu

    In the oscillation spectra of giant stars, nonradial modes may be seen to undergo avoided crossings, which produce a characteristic “mode bumping” of the otherwise uniform asymptotic p - and g -mode patterns in their respective echelle diagrams. Avoided crossings evolve very quickly relative to typical observational errors and are therefore extremely useful in determining precise ages of stars, particularly

    更新日期:2020-07-31
  • A Mid-infrared Flare in the Active Galaxy MCG-02-04-026: Dust Echo of a Nuclear Transient Event
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Luming Sun, Ning Jiang, Tinggui Wang, Hongyan Zhou, Liming Dou, Chenwei Yang, Xiang Pan, Zhenfeng Sheng, Zhihao Zhong, Lin Yan, and Ge Li

    We report the discovery of a mid-infrared (MIR) flare using Wide field Infrared Survey Explorer data in the center of the nearby Seyfert 1.9 galaxy MCG-02-04-026. The MIR flare began in the first half of 2014, peaked around the end of 2015, and faded in 2017. During these years, energy of more than 7 × 10 50 erg was released in the infrared, and the flare’s MIR color was generally turning red. We detected

    更新日期:2020-07-31
  • Non-LTE Calculations of the Mg i 12.32 μ m Line in a Flaring Atmosphere
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Jie Hong, Xianyong Bai, Ying Li, M. D. Ding, and Yuanyong Deng

    The infrared Mg i lines near 12 μ m are a pair of emission lines that are magnetically sensitive and have been used to measure solar magnetic fields. Here we calculate the response of the Mg i 12.32 μ m line during a flare and find that in our modeling this line has a complicated behavior. At the beginning of the flare heating, this line shows an intensity dimming at the line center. The intensity

    更新日期:2020-07-31
  • A 3 mm Chemical Exploration of Small Organics in Class I YSOs
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Romane Le Gal, Karin I. Öberg, Jane Huang, Charles J. Law, François Ménard, Bertrand Lefloch, Charlotte Vastel, Ana Lopez-Sepulcre, Cécile Favre, Eleonora Bianchi, and Cecilia Ceccarelli

    There is mounting evidence that the composition and structure of planetary systems are intimately linked to their birth environments. During the past decade, several spectral surveys probed the chemistry of the earliest stages of star formation and late planet-forming disks. However, very little is known about the chemistry of intermediate protostellar stages, i.e., class I young stellar objects (YSOs)

    更新日期:2020-07-31
  • Constraining Properties of the Next Nearby Core-collapse Supernova with Multimessenger Signals
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    MacKenzie L. Warren, Sean M. Couch, Evan P. O’Connor, and Viktoriya Morozova

    With the advent of modern neutrino and gravitational wave (GW) detectors, the promise of multimessenger detections of the next galactic core-collapse supernova (CCSN) has become very real. Such detections will give insight into the CCSN mechanism and the structure of the progenitor star, and may resolve longstanding questions in fundamental physics. In order to properly interpret these detections,

    更新日期:2020-07-31
  • Solar Vortex Tubes: Vortex Dynamics in the Solar Atmosphere
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Suzana S. A. Silva, Viktor Fedun, Gary Verth, Erico L. Rempel, and Sergiy Shelyag

    In this work, a state-of-the-art vortex detection method, Instantaneous Vorticity Deviation, is applied to locate three-dimensional vortex tube boundaries in numerical simulations of solar photospheric magnetoconvection performed by the MURaM code. We detected three-dimensional vortices distributed along intergranular regions and displaying coned shapes that extend from the photosphere to the low chromosphere

    更新日期:2020-07-31
  • Mapping Outflowing Gas in the Fermi Bubbles: A UV Absorption Survey of the Galactic Nuclear Wind
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Trisha Ashley, Andrew J. Fox, Edward B. Jenkins, Bart P. Wakker, Rongmon Bordoloi, Felix J. Lockman, Blair D. Savage, and Tanveer Karim

    Using new ultraviolet (UV) spectra of five background quasars from the Cosmic Origins Spectrograph on the Hubble Space Telescope, we analyze the low-latitude ( ##IMG## [http://ej.iop.org/images/0004-637X/898/2/128/apjab9ff8ieqn1.gif] {$| b| =20^\circ \mbox{--}30^\circ $} ) regions of the Fermi Bubbles, the giant gamma-ray-emitting lobes at the Galactic Center. We combine these data with previous UV

    更新日期:2020-07-31
  • Emergence of an Ultrared, Ultramassive Galaxy Cluster Core at z = 4
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Arianna S. Long, Asantha Cooray, Jingzhe Ma, Caitlin M. Casey, Julie L Wardlow, Hooshang Nayyeri, R. J. Ivison, Duncan Farrah, and Helmut Dannerbauer

    Recent simulations and observations of massive galaxy cluster evolution predict that the majority of stellar mass buildup happens within cluster members by z = 2, before cluster virialization. Protoclusters rich with dusty, star-forming galaxies (DSFGs) at z > 3 are the favored candidate progenitors for these massive galaxy clusters at z ∼ 0. We present here the first study analyzing stellar emission

    更新日期:2020-07-31
  • Tracking and Seismological Analysis of Multiple Coronal Loops in an Active Region
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    D. J. Pascoe, A. Smyrli, and T. Van Doorsselaere

    We present a new method to track the position and evolution of coronal loops designed for observations such as active regions in which multiple loops appear in close proximity or overlap with each other along the observational line of sight. The method is based on modeling a time–distance map containing one or more loops and fitting the modeled map to observational data, as opposed to the commonly

    更新日期:2020-07-31
  • A Global Nonhydrostatic Atmospheric Model with a Mass- and Energy-conserving Vertically Implicit Correction (VIC) Scheme
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-30
    Huazhi Ge, Cheng Li, Xi Zhang, and Dongwook Lee

    Global nonhydrostatic atmospheric models are becoming increasingly important for studying the climates of planets and exoplanets. However, such models suffer from computational difficulties due to the large aspect ratio between the horizontal and vertical directions. To overcome this problem, we developed a global model using a vertically implicit correction (VIC) scheme in which the integration time

    更新日期:2020-07-31
  • Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Xuefang Xu, Di Li, Y. Sophia Dai, Paul F. Goldsmith, and Gary A. Fuller

    We have analyzed the rotational properties of 12 clumps using 13 CO (1–0) and C 18 O (1–0) maps of the Five College Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii ( R ) in the range of 0.06–0.27 pc. The direction of clump elongation is not correlated with the direction of the velocity gradient. We measured the specific angular momentum (

    更新日期:2020-07-30
  • Ion-scale Current Structures in Short Large-amplitude Magnetic Structures
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Shan Wang, Li-Jen Chen, Naoki Bessho, Michael Hesse, Lynn B. Wilson III, Richard Denton, Jonathan Ng, Barbara Giles, Roy Torbert, and James Burch

    We investigate electric current structures in Short Large-Amplitude Magnetic Structures (SLAMS) in the terrestrial ion foreshock region observed by the Magnetospheric Multiscale mission. The structures with intense currents ( ##IMG## [http://ej.iop.org/images/0004-637X/898/2/121/apjab9b8bieqn1.gif] {$| J| \sim 1\,\mu {\rm{A}}\,{{\rm{m}}}^{-2}$} ) have scale lengths comparable to the local ion inertial

    更新日期:2020-07-30
  • On the Measurement of Handedness in Fermi Large Area Telescope Data
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Julia Asplund, Guðlaugur. Jóhannesson, and Axel Brandenburg

    A handedness in the arrival directions of high-energy photons from outside our Galaxy can be related to the helicity of an intergalactic magnetic field. Previous estimates by Tashiro et al. and Chen et al. showed a hint of a signal present in the photons observed by the Fermi Large Area Telescope (LAT). An update on the measurement of handedness in Fermi-LAT data is presented using more than 10 yr

    更新日期:2020-07-30
  • The Effect of Bars on the Ionized ISM: Optical Emission Lines from Milky Way Analogs
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Dhanesh Krishnarao, Christy Tremonti, Amelia Fraser-McKelvie, Katarina Kraljic, Nicholas Fraser Boardman, Karen L. Masters, Robert A. Benjamin, L. Matthew Haffner, Amy Jones, Zachary J. Pace, Gail Zasowski, Matthew Bershady, Dmitry Bizyaev, Jonathan Brinkmann, Joel R. Brownstein, Niv Drory, Kaike Pan, and Kai Zhang

    Gas interior to the bar of the Milky Way has recently been shown to be the closest example of a low-ionization (nuclear) emission region (LI(N)ER) in the universe. To better understand the nature of this gas, a sample of face-on galaxies with integral field spectroscopy is used to study the ionized gas conditions of 240 barred and 250 nonbarred galaxies, focusing on those that are most similar to the

    更新日期:2020-07-30
  • Stellar Characterization of Keck HIRES Spectra with The Cannon
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Malena Rice and John M. Brewer

    To accurately interpret the observed properties of exoplanets, it is necessary to first obtain a detailed understanding of host star properties. However, physical models that analyze stellar properties on a per-star basis can become computationally intractable for sufficiently large samples. Furthermore, these models are limited by the wavelength coverage of available spectra. We combine previously

    更新日期:2020-07-30
  • Morphological Classification of the Convective Regimes in Rotating Stars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Bradley W. Hindman, Nicholas A. Featherstone, and Keith Julien

    We present a set of numerical simulations that model the convection zones of solar-like stars. With this suite of numerical experiments, we explore how the nature of the convective structures transitions through a series of morphological regimes as the reduced Rayleigh number increases. Convection first manifests as a belt of rotationally aligned, convective, Taylor columns that circumscribes the equator

    更新日期:2020-07-30
  • IceCube Search for High-energy Neutrino Emission from TeV Pulsar Wind Nebulae
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    M. G. Aartsen, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, M. Ahrens, C. Alispach, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, J. Auffenberg, S. Axani, H. Bagherpour, X. Bai, A. Balagopal V., A. Barbano, S. W. Barwick, B. Bastian, V. Baum, S. Baur, R. Bay, J. J. Beatty, K.-H. Becker, J. Becker Tjus, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, G. Binder, D. Bindig, E. Blaufuss

    Pulsar wind nebulae (PWNe) are the main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit nonthermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma-rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution

    更新日期:2020-07-30
  • The Role of Inhomogeneities in Supernova Shock Breakout Emission
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Chris L. Fryer, Christopher J. Fontes, James S. Warsa, Pete W. A. Roming, Shane X. Coffing, and Suzannah R. Wood

    The breakout of a supernova blast wave from its progenitor star provides strong constraints on the star and its immediate surroundings. These surroundings are shaped by mass loss from the star and can include a wide variety of inhomogeneities. Here we present results of multidimensional radiation-hydrodynamics calculations of the interactions of the supernova blast wave with inhomogeneities in the

    更新日期:2020-07-30
  • NS 1987A in SN 1987A
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Dany Page, Mikhail V. Beznogov, Iván Garibay, James M. Lattimer, Madappa Prakash, and Hans-Thomas Janka

    The possible detection of a compact object in the remnant of SN 1987A presents an unprecedented opportunity to follow its early evolution. The suspected detection stems from an excess of infrared emission from a dust blob near the compact object’s predicted position. The infrared excess could be due to the decay of isotopes like 44 Ti, accretion luminosity from a neutron star or black hole, magnetospheric

    更新日期:2020-07-30
  • The Effect of Misalignment between the Rotation Axis and Magnetic Field on the Circumstellar Disk
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Shingo Hirano, Yusuke Tsukamoto, Shantanu Basu, and Masahiro N. Machida

    The formation of circumstellar disks is investigated using three-dimensional resistive magnetohydrodynamic simulations in which the initial prestellar cloud has a misaligned rotation axis with respect to the magnetic field. We examine the effects of (i) the initial angle difference between the global magnetic field and the cloud rotation axis ( θ 0 ) and (ii) the ratio of the thermal to gravitational

    更新日期:2020-07-30
  • Hurricane Genesis is Favorable on Terrestrial Exoplanets Orbiting Late-type M Dwarf Stars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-29
    Thaddeus D. Komacek, Daniel R. Chavas, and Dorian S. Abbot

    Hurricanes are one of the most extreme storm systems that occur on Earth, characterized by strong rainfall and fast winds. The terrestrial exoplanets that will be characterized with future infrared space telescopes orbit M dwarf stars. As a result, the best observable terrestrial exoplanets have vastly different climates from Earth, with a large dayside-to-nightside irradiation contrast and relatively

    更新日期:2020-07-30
  • Is T Tauri North a “Classical” T Tauri Star?
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    C. Flores, B. Reipurth, and M. S. Connelley

    We present high-resolution H - and K -band spectroscopic observations of the archetypal T Tauri star T Tau North. Synthetic spectral modeling is used to derive the K -band temperature, surface gravity, magnetic field strength, and rotational velocity for this star. The K -band spectroscopic temperature measured is ##IMG## [http://ej.iop.org/images/0004-637X/898/2/109/apjab9e67ieqn1.gif] {${T}_{K \mbox{-}

    更新日期:2020-07-29
  • How Flow Isolation May Set the Mass Scale for Super-Earth Planets
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    M. M. Rosenthal and R. A. Murray-Clay

    Much recent work on planet formation has focused on the growth of planets by accretion of grains whose aerodynamic properties make them marginally coupled to the nebular gas, a theory commonly referred to as “pebble accretion.” While the rapid growth rates of pebble accretion can ameliorate some problems in planet formation theory, they raise new concerns as well. A particular issue is the preponderance

    更新日期:2020-07-29
  • Nuclear X-Ray Activity in Low-surface-brightness Galaxies: Prospects for Constraining the Local Black Hole Occupation Fraction with a Chandra Successor Mission
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Edmund J. Hodges-Kluck, Elena Gallo, Anil Seth, Jenny Greene, and Vivienne Baldassare

    About half of nearby galaxies have a central surface brightness ≥1 mag below that of the sky. The overall properties of these low-surface-brightness galaxies (LSBGs) remain understudied, and in particular we know very little about their massive black hole population. This gap must be closed to determine the frequency of massive black holes at z = 0 as well as to understand their role in regulating

    更新日期:2020-07-29
  • ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP). I. Detection of New Hot Corinos with the ACA
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Shih-Ying Hsu, Sheng-Yuan Liu, Tie Liu, Dipen Sahu, Naomi Hirano, Chin-Fei Lee, Ken’ichi Tatematsu, Gwanjeong Kim, Mika Juvela, Patricio Sanhueza, Jinhua He, Doug Johnstone, Sheng-Li Qin, Leonardo Bronfman, Huei-Ru Vivien Chen, Somnath Dutta, David J. Eden, Kai-Syun Jhan, Kee-Tae Kim, Yi-Jehng Kuan, Woojin Kwon, Chang Won Lee, Jeong-Eun Lee, Anthony Moraghan, M. G. Rawlings, Hsien Shang, Archana Soam

    We report the detection of four new hot corino sources, G211.47–19.27S, G208.68–19.20N1, G210.49–19.79W, and G192.12–11.10, from a survey study of Planck Galactic Cold Clumps in the Orion Molecular Cloud Complex with the Atacama Compact Array. Three sources had been identified as low-mass Class 0 protostars in the Herschel Orion Protostar Survey. One source in the λ Orionis region is first reported

    更新日期:2020-07-29
  • Revisiting the Sun’s Strong Differential Rotation along Radial Lines
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Loren I. Matilsky, Bradley W. Hindman, and Juri Toomre

    Current state-of-the-art models of the solar convection zone consist of solutions to the Navier–Stokes equations in rotating, 3D spherical shells. Such models are highly sensitive to the choice of boundary conditions. Here we present two suites of simulations differing only in their outer thermal boundary condition, which is either one of fixed entropy (FE) or fixed flux (FF; corresponding to a fixed

    更新日期:2020-07-29
  • A Large-scale, Regular Intergalactic Magnetic Field Associated with Stephan’s Quintet?
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Błażej Nikiel-Wroczyński, Marian Soida, George Heald, and Marek Urbanik

    Regular magnetic fields are frequently found within and in the outskirts of galaxies, but their presence, properties, and origin has not yet been established for galaxy groups. On the basis of broadband radio polarimetric imaging with the Westerbork Synthesis Radio Telescope, we made use of rotation measure synthesis to disentangle contributions from magnetic fields on various scales for several polarized

    更新日期:2020-07-29
  • Deep Learning Prediction of the Broad Ly α Emission Line of Quasars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Hassan Fathivavsari

    We have employed a deep neural network, or deep learning , to predict the flux and the shape of the broad Ly α emission lines in the spectra of quasars. We use 17,870 high signal-to-noise ratio (S/N > 15) quasar spectra from the Sloan Digital Sky Survey Data Release 14 to train the model and evaluate its performance. The Si iv , C iv , and C iii] broad emission lines are used as the input to the neural

    更新日期:2020-07-29
  • Spectral Features in Field-aligned Solar Wind Turbulence from Parker Solar Probe Observations
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    L.-L. Zhao, G. P. Zank, L. Adhikari, M. Nakanotani, D. Telloni, and F. Carbone

    Parker Solar Probe (PSP) observed a large variety of Alfvénic fluctuations in the fast and slow solar wind flow during its two perihelia. The properties of Alfvénic solar wind turbulence have been studied for decades in the near-Earth environment. A spectral index of −5/3 or −2 for magnetic field fluctuations has been observed using spacecraft measurements, which can be explained by turbulence theories

    更新日期:2020-07-29
  • No Redshift Evolution in the Broad-line-region Metallicity up to z = 7.54: Deep Near-infrared Spectroscopy of ULAS J1342+0928
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Masafusa Onoue, Eduardo Bañados, Chiara Mazzucchelli, Bram P. Venemans, Jan-Torge Schindler, Fabian Walter, Joseph F. Hennawi, Irham Taufik Andika, Frederick B. Davies, Roberto Decarli, Emanuele P. Farina, Knud Jahnke, Tohru Nagao, Nozomu Tominaga, and Feige Wang

    We present deep (9 hr) Gemini-N/Gemini Near-InfraRed Spectrograph near-infrared spectroscopic observations of ULAS J1342+0928, a luminous quasar at z = 7.54. Various broad emission lines were detected, as well as the underlying continuum and iron forests over the rest-frame wavelength 970–2930 Å. There is a clear trend that higher-ionization emission lines show larger blueshifts with C iv ##IMG## [http://ej

    更新日期:2020-07-29
  • Negative Magnetic Diffusivity β Replacing the α Effect in the Helical Dynamo
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-28
    Kiwan Park

    In the Sun, the converting process of a poloidal magnetic field ( B pol ) from a toroidal field ( B tor ) is essential to sustaining the solar magnetic fields. However, the converting process, dominated by α and β effects, is not yet clearly understood. Conventional theories expect that the α effect should be quenched as the magnetic field grows. Also, plasma kinetic energy is thought to diffuse magnetic

    更新日期:2020-07-29
  • Imaging and Spectral Study on the Null Point of a Fan-spine Structure During a Solar Flare
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Shuhong Yang, Qingmin Zhang, Zhi Xu, Jun Zhang, Ze Zhong, and Yang Guo

    Using the multi-instrument observations, we make the first simultaneous imaging and spectral study on the null point of a fan-spine magnetic topology during a solar flare. When magnetic reconnection occurs at the null point, the fan-spine configuration brightens in the (extreme-)ultraviolet channels. In the H α images, the fan-spine structure is partly filled and outlined by the bidirectional material

    更新日期:2020-07-28
  • On the Determination of Rotation Velocity and Dynamical Mass of Galaxies Based on Integrated H i Spectra
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Niankun Yu, Luis C. Ho, and Jing Wang

    The integrated 21 cm H i emission profile of a galaxy encodes valuable information on the kinematics, spatial distribution, and dynamical state of its cold interstellar medium. The line width, in particular, reflects the rotation velocity of the galaxy, which, in combination with a size scale, can be used to constrain the dynamical mass of the system. We introduce a new method based on the concept

    更新日期:2020-07-28
  • Supervised Convolutional Neural Networks for Classification of Flaring and Nonflaring Active Regions Using Line-of-sight Magnetograms
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Shamik Bhattacharjee, Rasha Alshehhi, Dattaraj B. Dhuri, and Shravan M. Hanasoge

    Solar flares are explosions in the solar atmosphere that release intense bursts of short-wavelength radiation and are capable of producing severe space-weather. Flares release free energy built up in coronal fields, which are rooted in active regions (ARs) on the photosphere, via magnetic reconnection. The exact processes that lead to reconnection are not fully known and therefore reliable forecasting

    更新日期:2020-07-28
  • Radio Echo in the Turbulent Corona and Simulations of Solar Drift-pair Radio Bursts
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Alexey A. Kuznetsov, Nicolina Chrysaphi, Eduard P. Kontar, and Galina Motorina

    Drift-pair bursts are an unusual type of solar low-frequency radio emission, which appear in the dynamic spectra as two parallel drifting bright stripes separated in time. Recent imaging spectroscopy observations allowed for the quantitative characterization of the drifting pairs in terms of source size, position, and evolution. Here, the drift-pair parameters are qualitatively analyzed and compared

    更新日期:2020-07-28
  • Photohadronic Model for the Neutrino and Gamma-Ray Emission from TXS 0506+056
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Sarira Sahu, Carlos E. López Fortín, and Shigehiro Nagataki

    The detection of a high-energy muon neutrino on 2017 September 22 by the IceCube neutrino detector coincides with the multiwavelength flaring from the BL Lac object TXS 0506+056, most likely confirming an active galactic nucleus as a source of high energy cosmic rays and neutrinos. Using the photohadronic model, we have explained the very high energy γ -rays observed by MAGIC telescopes a few days

    更新日期:2020-07-28
  • Cosmological Model-independent Constraints on Spatial Curvature from Strong Gravitational Lensing and SN Ia Observations
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Bo Wang, Jing-Zhao Qi, Jing-Fei Zhang, and Xin Zhang

    Applying the distance sum rule in strong gravitational lensing (SGL) and SN Ia observations, one can provide an interesting cosmological model-independent method to determine the cosmic curvature parameter Ω k . In this paper, with the newly compiled data sets including 161 galactic-scale SGL systems and 1048 SN Ia data, we place constraints on Ω k within the framework of three types of lens models

    更新日期:2020-07-28
  • Was GW190412 Born from a Hierarchical 3 + 1 Quadruple Configuration?
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Adrian S. Hamers and Mohammadtaher Safarzadeh

    The gravitational wave source GW190412 is a binary black hole (BBH) merger with three unique properties: (i) its mass ratio is about 0.28, the lowest found so far, (ii) it has a relatively high positive effective spin parameter ##IMG## [http://ej.iop.org/images/0004-637X/898/2/99/apjab9b27ieqn1.gif] {${\chi }_{\mathrm{eff}}=0.25$} , and (iii) it is observed to be precessing due to in-plane projected

    更新日期:2020-07-28
  • Origin of Large Meteoritic SiC Stardust Grains in Metal-rich AGB Stars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Maria Lugaro, Borbála Cseh, Blanka Világos, Amanda I. Karakas, Paolo Ventura, Flavia Dell’Agli, Reto Trappitsch, Melanie Hampel, Valentina D’Orazi, Claudio B. Pereira, Giuseppe Tagliente, Gyula M. Szabó, Marco Pignatari, Umberto Battino, Ashley Tattersall, Mattias Ek, Maria Schönbächler, Josef Hron, and Larry R. Nittler

    Stardust grains that originated in ancient stars and supernovae are recovered from meteorites and carry the detailed composition of their astronomical sites of origin. We present evidence that the majority of large ( μ m-sized) meteoritic silicon carbide (SiC) grains formed in C-rich asymptotic giant branch (AGB) stars that were more metal-rich than the Sun. In the framework of the slow neutron captures

    更新日期:2020-07-28
  • An Evolutionary Study of Volatile Chemistry in Protoplanetary Disks
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Jennifer B. Bergner, Karin I. Öberg, Edwin A. Bergin, Sean M. Andrews, Geoffrey A. Blake, John M. Carpenter, L. Ilsedore Cleeves, Viviana V. Guzmán, Jane Huang, Jes K. Jørgensen, Chunhua Qi, Kamber R. Schwarz, Jonathan P. Williams, and David J. Wilner

    The volatile composition of a planet is determined by the inventory of gas and ice in the parent disk. The volatile chemistry in the disk is expected to evolve over time, though this evolution is poorly constrained observationally. We present Atacama Large Millimeter/submillimeter Array observations of C 18 O, C 2 H, and the isotopologues H 13 CN, HC 15 N, and DCN toward five Class 0/I disk candidates

    更新日期:2020-07-28
  • Obliquity of an Earth-like Planet from Frequency Modulation of Its Direct-imaged Lightcurve: Mock Analysis from General Circulation Model Simulation
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Yuta Nakagawa, Takanori Kodama, Masaki Ishiwatari, Hajime Kawahara, Yasushi Suto, Yoshiyuki O. Takahashi, George L. Hashimoto, Kiyoshi Kuramoto, Kensuke Nakajima, Shin-ichi Takehiro, and Yoshi-Yuki Hayashi

    Direct-imaging techniques of exoplanets have made significant progress recently and will eventually enable monitoring of photometric and spectroscopic signals of Earth-like habitable planets. The presence of clouds, however, would remain as one of the most uncertain components in deciphering such direct-imaged signals of planets. We attempt to examine how the planetary obliquity produces different

    更新日期:2020-07-28
  • The Evolutionary Track of H/He Envelopes of the Observed Population of Sub-Neptunes and Super-Earths
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-27
    Raissa Estrela, Mark R. Swain, Akash Gupta, Christophe Sotin, and Adriana Valio

    The observational detection of a localized reduction in the small planet occurrence rate, sometimes termed a “gap,” is an exciting discovery because of the implications for planet evolutionary history. This gap appears to define a transition region in which sub-Neptune planets are believed to have lost their H/He envelopes, potentially by photoevaporation or core powered mass loss, and have thus been

    更新日期:2020-07-28
  • Vibrational Spectroscopy of a Potential Interstellar Ion: Protonated Methyl Formate
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-26
    Kuntal Chatterjee and Otto Dopfer

    The abundance of methyl formate (MF, HCOOCH 3 ) in star-forming regions of the interstellar medium (ISM) suggests the presence of protonated MF (H + MF). However, no spectroscopic data exist for isolated H + MF. Here, we address the vibrational properties of H + MF and its H + MF-L n ≤2 clusters (L = Ar/N 2 ) by infrared photodissociation (IRPD) spectroscopy and density functional theory calculations

    更新日期:2020-07-27
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