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  • A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026–4536
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Matthew A. Cornachione, Christopher W. Morgan, Martin Millon, Misty C. Bentz, Frederic Courbin, Vivien Bonvin, and Emilio E. Falco

    We use 13 seasons of R -band photometry from the 1.2 m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply imaged lensed quasar WFI 2026–4536. The lightcurves exhibit ∼0.2 mag of uncorrelated variability across all epochs and a prominent single feature of ∼0.1 mag within a single season. We analyze this variability to constrain the size of the quasar’s accretion

    更新日期:2020-06-03
  • A Hybrid Method of Accurate Classification for Blazars of Uncertain Type in Fermi-LAT Catalogs
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Yijun Xu, Weirong Huang, Hui Deng, Ying Mei, and Feng Wang

    Significant progress in the classification of Fermi unassociated sources has led to an increase in the number of blazars being found. The optical spectrum is effectively used to classify the blazars into two groups such as BL Lac objects and flat spectrum radio quasars (FSRQs). However, the accurate classification of the blazars without optical spectrum information, i.e., blazars of uncertain type

    更新日期:2020-06-03
  • A New Facility for Airborne Solar Astronomy: NASA’s WB-57 at the 2017 Total Solar Eclipse
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Amir Caspi, Daniel B. Seaton, Constantine C. C. Tsang, Craig E. DeForest, Paul Bryans, Edward E. DeLuca, Steven Tomczyk, Joan T. Burkepile, Thomas “Tony” Casey, John Collier, Donald “DD” Darrow, Dominic Del Rosso, Daniel D. Durda, Peter T. Gallagher, Leon Golub, Matthew Jacyna, David “DJ” Johnson, Philip G. Judge, Cary “Diddle” Klemm, Glenn T. Laurent, Johanna Lewis, Charles J. Mallini, Thomas “Duster”

    NASA’s WB-57 High Altitude Research Program provides a deployable, mobile, and stratospheric platform for scientific research. Airborne platforms are of particular value for making coronal observations during total solar eclipses because of their ability both to follow the Moon’s shadow and to get above most of the atmospheric air mass that can interfere with astronomical observations. We used the

    更新日期:2020-06-03
  • AGN X-Ray Irradiation of CO Gas in NGC 2110 Revealed by Chandra and ALMA
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Taiki Kawamuro, Takuma Izumi, Kyoko Onishi, Masatoshi Imanishi, Dieu D. Nguyen, and Shunsuke Baba

    We report spatial distributions of the Fe–K α line at 6.4 keV and the CO( J = 2–1) line at 230.538 GHz in NGC 2110, which are, respectively, revealed by Chandra and Atacama Large Millimeter/submillimeter Array (ALMA) at ≈0.″5. A Chandra 6.2–6.5 keV to 3.0–6.0 keV image suggests that the Fe–K α emission extends preferentially in a northwest to southeast direction out to ≈3″, or ∼500 pc, on each side

    更新日期:2020-06-03
  • A Detailed Analysis of the Cloud Structure and Dynamics in Aquila Rift
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Tomomi Shimoikura, Kazuhito Dobashi, Yoshiko Hatano, and Fumitaka Nakamura

    We present maps in several molecular emission lines of a 1 square degree region covering the W40 and Serpens South molecular clouds belonging to the Aquila Rift complex. The observations were made with the 45 m telescope at the Nobeyama Radio Observatory. We found that the 12 CO and 13 CO emission lines consist of several velocity components with different spatial distributions. The component that

    更新日期:2020-06-03
  • KIC 10736223: An Algol-type Eclipsing Binary That Has Just Undergone the Rapid Mass-transfer Stage
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Xinghao Chen, Xiaobin Zhang, Yan Li, Hailiang Chen, Changqing Luo, Jie Su, Xuefei Chen, and Zhanwen Han

    This paper reports the discovery of an Algol system KIC 10736223 that just passed the rapid mass transfer stage. From the light-curve and radial-velocity modeling we find KIC 10736223 to be a detached Algol system with the less-massive secondary nearly filling its Roche lobe. Based on the short-cadence Kepler data, we analyzed intrinsic oscillations of the pulsator and identified six secured independent

    更新日期:2020-06-03
  • New Type Ia Supernova Yields and the Manganese and Nickel Problems in the Milky Way and Dwarf Spheroidal Galaxies
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Chiaki Kobayashi, Shing-Chi Leung, and Ken’ichi Nomoto

    In our quest to identify the progenitors of Type Ia supernovae (SNe Ia), we first update the nucleosynthesis yields for both near-Chandrasekhar- (Ch) and sub-Ch-mass white dwarfs (WDs) for a wide range of metallicities with our 2D hydrodynamical code and the latest nuclear reaction rates. We then include the yields in our galactic chemical evolution code to predict the evolution of elemental abundances

    更新日期:2020-06-03
  • EvryFlare. II. Rotation Periods of the Cool Flare Stars in TESS across Half the Southern Sky
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Nathan Galliher, Amy Glazier, Octavi Fors, Daniel del Ser, and Joshua Haislip

    We measure rotation periods and sinusoidal amplitudes in Evryscope light curves for 122 two-minute K5–M4 TESS targets selected for strong flaring. The Evryscope array of telescopes has observed all bright nearby stars in the south, producing 2-minute cadence light curves since 2016. Long-term, high-cadence observations of rotating flare stars probe the complex relationship between stellar rotation

    更新日期:2020-06-03
  • The Ultraluminous Ly α Luminosity Function at z = 6.6
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    A. J. Taylor, A. J. Barger, L. L. Cowie, E. M. Hu, and A. Songaila

    We present the luminosity function (LF) for ultraluminous Ly α emitting galaxies (LAEs) at z = 6.6. We define ultraluminous LAEs (ULLAEs) as galaxies with ##IMG## [http://ej.iop.org/images/0004-637X/895/2/132/apjab8adaieqn1.gif] {$\mathrm{log}L(\mathrm{Ly}\alpha )\gt 43.5$} erg s −1 . We select our main sample using the g ′, r ′, i ′, z ′, and NB921 observations of a wide-area (30 deg 2 ) Hyper Suprime-Cam

    更新日期:2020-06-03
  • Detection of the Strongest Magnetic Field in a Sunspot Light Bridge
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    J. S. Castellanos Durán, Andreas Lagg, Sami K. Solanki, and Michiel van Noort

    Traditionally, the strongest magnetic fields on the Sun have been measured in sunspot umbrae. More recently, however, much stronger fields have been measured at the ends of penumbral filaments carrying the Evershed and counter-Evershed flows. Superstrong fields have also been reported within a light bridge separating two umbrae of opposite polarities. We aim to accurately determine the strengths of

    更新日期:2020-06-03
  • The Low Effective Spin of Binary Black Holes and Implications for Individual Gravitational-wave Events
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Simona Miller, Thomas A. Callister, and Will M. Farr

    While the Advanced LIGO and Virgo gravitational-wave (GW) experiments now regularly observe binary black hole (BBH) mergers, the evolutionary origin of these events remains a mystery. Analysis of the BBH spin distribution may shed light on this mystery, offering a means of discriminating between different binary formation channels. Using the data from Advanced LIGO and Virgo’s first and second observing

    更新日期:2020-06-03
  • The Evolution of Dust Disk Sizes from a Homogeneous Analysis of 1–10 Myr old Stars
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Nathanial Hendler, Ilaria Pascucci, Paola Pinilla, Marco Tazzari, John Carpenter, Renu Malhotra, and Leonardo Testi

    We utilize ALMA archival data to estimate the dust disk size of 152 protoplanetary disks in Lupus (1–3 Myr), Chamaeleon I (2–3 Myr), and Upper-Sco (5–11 Myr). We combine our sample with 47 disks from Tau/Aur and Oph whose dust disk radii were estimated, as here, through fitting radial profile models to visibility data. We use these 199 homogeneously derived disk sizes to identify empirical disk–disk

    更新日期:2020-06-03
  • Global Energetics of Solar Flares. X. Petschek Reconnection Rate and Alfvén Mach Number of Magnetic Reconnection Outflows
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Markus J. Aschwanden

    We investigate physical scaling laws for magnetic energy dissipation in solar flares, in the framework of the Sweet–Parker model and the Petschek model. We find that the total dissipated magnetic energy E diss in a flare depends on the mean magnetic field component B f associated with the free energy E f , the length scale L of the magnetic area, the hydrostatic density scale height λ of the solar

    更新日期:2020-06-03
  • Kinematic Decomposition of IllustrisTNG Disk Galaxies: Morphology and Relation with Morphological Structures
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Min Du, Luis C. Ho, Victor P. Debattista, Annalisa Pillepich, Dylan Nelson, Dongyao Zhao, and Lars Hernquist

    We recently developed an automated method, auto-GMM , to decompose simulated galaxies. It extracts kinematic structures in an accurate, efficient, and unsupervised way. We use auto-GMM to study the stellar kinematic structures of disk galaxies from the TNG100 run of IllustrisTNG . We identify four to five structures that are commonly present among the diverse galaxy population. Structures having strong

    更新日期:2020-06-03
  • Swift Monitoring of M51: A 38 day Superorbital Period for the Pulsar ULX7 and a New Transient Ultraluminous X-Ray Source
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Murray Brightman, Hannah Earnshaw, Felix Fürst, Fiona A. Harrison, Marianne Heida, Gianluca Israel, Sean Pike, Daniel Stern, and Dominic J. Walton

    We present the results from a monitoring campaign made with the Neil Gehrels Swift Observatory of the M51 galaxies, which contain several variable ultraluminous X-ray sources (ULXs). The ongoing campaign started in 2018 May, and we report here on ∼1.5 yr of observations. The campaign, which consists of 106 observations, has a typical cadence of 3–6 days, and has the goal of determining the long-term

    更新日期:2020-06-03
  • Cosmic Spin and Mass Evolution of Black Holes and Its Impact
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-03
    Dipanweeta Bhattacharyya and A. Mangalam

    We build an evolution model of the central black hole that depends on the processes of gas accretion, the capture of stars, mergers, and electromagnetic torque. In the case of gas accretion in the presence of cooling sources, the flow is momentum driven, after which the black hole reaches a saturated mass; subsequently, it grows only by stellar capture and mergers. We model the evolution of the mass

    更新日期:2020-06-03
  • Galaxy Merger Rates up to z ∼ 3 Using a Bayesian Deep Learning Model: A Major-merger Classifier Using IllustrisTNG Simulation Data
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Leonardo Ferreira, Christopher J. Conselice, Kenneth Duncan, Ting-Yun Cheng, Alex Griffiths, and Amy Whitney

    Merging is potentially the dominant process in galaxy formation, yet there is still debate about its history over cosmic time. To address this, we classify major mergers and measure galaxy merger rates up to z ∼ 3 in all five CANDELS fields (UDS, EGS, GOODS-S, GOODS-N, COSMOS) using deep learning convolutional neural networks trained with simulated galaxies from the IllustrisTNG cosmological simulation

    更新日期:2020-06-02
  • Physics of Pair Producing Gaps in Black Hole Magnetospheres. II. General Relativity
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Alexander Y. Chen and Yajie Yuan

    This is the second paper in a series where we examine the physics of pair producing gaps in low-luminosity accreting supermassive black hole systems. In this paper, we carry out time-dependent self-consistent fully general relativistic 1D particle-in-cell simulations of the gap, including full inverse Compton scattering and photon tracking. Similar to the previous paper, we find a highly time-dependent

    更新日期:2020-06-02
  • A Pre-main-sequence γ Dor- δ Sct Hybrid with Extremely Slow Internal Rotation in a Short-period Eclipsing Binary KIC 9850387 Revealed by Asteroseismology
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Xiaobin Zhang, Xinghao Chen, Haotong Zhang, Jianning Fu, and Yan Li

    A complete understanding of the formation process of close binaries relies on the reliable determination of their masses and ages, as well as the interior structure of pre-main-sequence (PMS) binaries. PMS eclipsing binaries containing stellar oscillations are therefore benchmarks since the binarity makes it possible to measure the masses and radii independently with great accuracy, while stellar oscillations

    更新日期:2020-06-02
  • Coronal Magnetic Field Topology from Total Solar Eclipse Observations
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Benjamin Boe, Shadia Habbal, and Miloslav Druckmüller

    Measuring the global magnetic field of the solar corona remains exceptionally challenging. The fine-scale density structures observed in white-light images taken during total solar eclipses are currently the best proxies for inferring the magnetic field direction in the corona from the solar limb out to several solar radii ( R ⊙ ). We present, for the first time, the topology of the coronal magnetic

    更新日期:2020-06-02
  • Looking at Blazar Light-curve Periodicities with Gaussian Processes
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Stefano Covino, Marco Landoni, Angela Sandrinelli, and Aldo Treves

    Temporal analysis of blazar flux is a powerful tool to draw inferences about the emission processes and physics of these sources. In the most general case, the available light curves are irregularly sampled and influenced by gaps, and in addition are also affected by correlated noise, making their analysis complicated. Gaussian processes may offer a viable tool to assess the statistical significance

    更新日期:2020-06-02
  • Fitting the Nonlinear Matter Bispectrum by the Halofit Approach
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Ryuichi Takahashi, Takahiro Nishimichi, Toshiya Namikawa, Atsushi Taruya, Issha Kayo, Ken Osato, Yosuke Kobayashi, and Masato Shirasaki

    We provide a new fitting formula of the matter bispectrum in the nonlinear regime calibrated by high-resolution cosmological N -body simulations of 41 cold dark matter ( w CDM, w = constant) models around the Planck 2015 best-fit parameters. As the parameterization in our fitting function is similar to that in Halofit, our fitting is named BiHalofit. The simulation volume is sufficiently large ( ##IMG##

    更新日期:2020-06-02
  • The Ionizing Photon Production Efficiency ( ξ ion ) of Lensed Dwarf Galaxies at z ∼ 2
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Najmeh Emami, Brian Siana, Anahita Alavi, Timothy Gburek, William R. Freeman, Johan Richard, Daniel R. Weisz, and Daniel P. Stark

    We measure the ionizing photon production efficiency ( ξ ion ) of low-mass galaxies (10 7.8 –10 9.8 M ⊙ ) at1.4 < z < 2.7 to better understand the contribution of dwarf galaxies to the ionizing background and reionization. We target galaxies that are magnified by strong-lensing galaxy clusters and use Keck/MOSFIRE to measure nebular emission-line fluxes and Hubble Space Telescope to measure the rest-UV

    更新日期:2020-06-02
  • ALMA ACA and Nobeyama Observations of Two Orion Cores in Deuterated Molecular Lines
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Ken’ichi Tatematsu, Tie Liu, Gwanjeong Kim, Hee-Weon Yi, Jeong-Eun Lee, Naomi Hirano, Sheng-Yuan Liu, Satoshi Ohashi, Patricio Sanhueza, James Di Francesco, Neal J. Evans II, Gary A. Fuller, Ryo Kandori, Minho Choi, Miju Kang, Siyi Feng, Tomoya Hirota, Takeshi Sakai, Xing Lu, Quang Nguyên Lu’o’ng, Mark A. Thompson, Yuefang Wu, Di Li, Kee-Tae Kim, Ke Wang, Isabelle Ristorcelli, Mika Juvela, and L. Viktor

    We mapped two molecular cloud cores in the Orion A cloud with the 7 m Array of the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeterArray (ALMA) and with the Nobeyama 45 m radio telescope. These cores have bright N 2 D + emission in single-pointing observations with the Nobeyama 45 m radio telescope, have a relatively high deuterium fraction, and are thought to be close to the

    更新日期:2020-06-02
  • A General Formulation for Computing Spherical Helioseismic Sensitivity Kernels while Incorporating Systematical Effects
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Jishnu Bhattacharya, Shravan M. Hanasoge, and Katepalli R. Sreenivasan

    As helioseismology matures and turns into a precision science, modeling finite-frequency, geometric, and systematical effects is becoming increasingly important. Here we introduce a general formulation for treating perturbations of arbitrary tensor rank in spherical geometry using fundamental ideas of quantum mechanics and their extensions in geophysics. We include line-of-sight projections and center-to-limb

    更新日期:2020-06-02
  • On the Relation between the Hard X-Ray Photon Index and Accretion Rate for Super-Eddington Accreting Quasars
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Jian Huang, Bin Luo, Pu Du, Chen Hu, Jian-Min Wang, and Yi-Jia Li

    We investigate whether the correlation between the hard X-ray photon index ( ##IMG## [http://ej.iop.org/images/0004-637X/895/2/114/apjab9019ieqn1.gif] {${\rm{\Gamma }}$} ) and accretion rate for super-Eddington accreting quasars is different from that for sub-Eddington accreting quasars. We construct a sample of 113 bright quasars from the Sloan Digital Sky Survey Data Release 14 quasar catalog, with

    更新日期:2020-06-02
  • SN 2013aa and SN 2017cbv: Two Sibling Type Ia Supernovae in the Spiral Galaxy NGC 5643
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Christopher R. Burns, Chris Ashall, Carlos Contreras, Peter Brown, Maximilian Stritzinger, M. M. Phillips, Ricardo Flores, Nicholas B. Suntzeff, Eric Y. Hsiao, Syed Uddin, Joshua D. Simon, Kevin Krisciunas, Abdo Campillay, Ryan J. Foley, Wendy L. Freedman, Lluís Galbany, Consuelo González, Peter Hoeflich, S. Holmbo, Charles D. Kilpatrick, Robert P. Kirshner, Nidia Morrell, Nahir Muñoz-Elgueta, Anthony

    We present photometric and spectroscopic observations of SN 2013aa and SN 2017cbv, two nearly identical type Ia supernovae (SNe Ia) in the host galaxy NGC 5643. The optical photometry has been obtained using the same telescope and instruments used by the Carnegie Supernova Project. This eliminates most instrumental systematics and provides light curves in a stable and well-understood photometric system

    更新日期:2020-06-02
  • XMM-Newton and NICER Measurement of the Rms Spectrum of the Millihertz Quasiperiodic Oscillations in the Neutron-star Low-mass X-Ray Binary 4U 1636–53
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-02
    Ming Lyu, Guobao Zhang, Mariano Méndez, D. Altamirano, G. C. Mancuso, Fu-Yuan Xiang, and Huaping Xiao

    We used two XMM-Newton and six Neutron Star Interior Composition Explorer observations to investigate the fractional rms amplitude of the millihertz quasiperiodic oscillations (mHz QPOs) in the neutron-star low-mass X-ray binary 4U 1636–53. We studied, for the first time, the fractional rms amplitude of the mHz QPOs versus energy in 4U 1636–53 down to 0.2 keV. We find that, as the energy increases

    更新日期:2020-06-02
  • Efficient Methanol Production on the Dark Side of a Prestellar Core
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Jorma Harju, Jaime E. Pineda, Anton I. Vasyunin, Paola Caselli, Stella S. R. Offner, Alyssa A. Goodman, Mika Juvela, Olli Sipilä, Alexandre Faure, Romane Le Gal, Pierre Hily-Blant, João Alves, Luca Bizzocchi, Andreas Burkert, Hope Chen, Rachel K. Friesen, Rolf Güsten, Philip C. Myers, Anna Punanova, Claire Rist, Erik Rosolowsky, Stephan Schlemmer, Yancy Shirley, Silvia Spezzano, Charlotte Vastel, and

    We present Atacama Large Millimeter/submillimeter Array maps of the starless molecular cloud core Ophiuchus/H-MM1 in the lines of deuterated ammonia (ortho- ##IMG## [http://ej.iop.org/images/0004-637X/895/2/101/apjab8f93ieqn1.gif] {${\mathrm{NH}}_{2}{\rm{D}}$} ), methanol ( ##IMG## [http://ej.iop.org/images/0004-637X/895/2/101/apjab8f93ieqn2.gif] {${\mathrm{CH}}_{3}\mathrm{OH}$} ), and sulfur monoxide

    更新日期:2020-06-01
  • SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). IV. Spatial Clustering and Halo Masses of Submillimeter Galaxies
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Chen-Fatt Lim, Chian-Chou Chen, Ian Smail, Wei-Hao Wang, Wei-Leong Tee, Yen-Ting Lin, Douglas Scott, Yoshiki Toba, Yu-Yen Chang, YiPing Ao, Arif Babul, Andy Bunker, Scott C. Chapman, David L. Clements, Christopher J. Conselice, Yu Gao, Thomas R. Greve, Luis C. Ho, Sungwook E. Hong, Ho Seong Hwang, Maciej Koprowski, Michał J. Michałowski, Hyunjin Shim, Xinwen Shu, and James M. Simpson

    We analyze an extremely deep 450 μ m image (1 σ = 0.56 mJy beam −1 ) of a ≃300 arcmin 2 area in the CANDELS/COSMOS field as part of the Sub-millimeter Common User Bolometric Array-2 Ultra Deep Imaging EAO Survey. We select a robust (signal-to-noise ratio ≥4) and flux-limited (≥4 mJy) sample of 164 submillimeter galaxies (SMGs) at 450 μ m that have K -band counterparts in the COSMOS2015 catalog identified

    更新日期:2020-06-01
  • Measuring Turbulent Motion in Planet-forming Disks with ALMA: A Detection around DM Tau and Nondetections around MWC 480 and V4046 Sgr
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Kevin Flaherty, A. Meredith Hughes, Jacob B. Simon, Chunhua Qi, Xue-Ning Bai, Alyssa Bulatek, Sean M. Andrews, David J. Wilner, and Ágnes Kóspál

    Turbulence is a crucial factor in many models of planet formation, but it has only been directly constrained among a small number of planet-forming disks. Building on the upper limits on turbulence placed in disks around HD 163296 and TW Hya, we present ALMA CO J = 2–1 line observations at ∼0.″3 (20–50 au) resolution and 80 ms −1 channel spacing of the disks around DM Tau, MWC 480, and V4046 Sgr. Using

    更新日期:2020-06-01
  • Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Grigorios Katsoulakos and Frank M. Rieger

    The detection of rapidly variable gamma-ray emission in active galactic nuclei has generated renewed interest in magnetospheric particle acceleration and emission scenarios. In order to explore its potential, we study the possibility of steady gap acceleration around the null surface of a rotating black hole magnetosphere. We employ a simplified (1D) description along with the general relativistic

    更新日期:2020-06-01
  • The Chemistry of Cosmic Dust Analogs from C, C 2 , and C 2 H 2 in C-rich Circumstellar Envelopes
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Gonzalo Santoro, Lidia Martínez, Koen Lauwaet, Mario Accolla, Guillermo Tajuelo-Castilla, Pablo Merino, Jesús M. Sobrado, Ramón J. Peláez, Víctor J. Herrero, Isabel Tanarro, Álvaro Mayoral, Marcelino Agúndez, Hassan Sabbah, Christine Joblin, José Cernicharo, and José Ángel Martín-Gago

    Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch stars (AGBs). In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene, are the most abundant species after H 2 and CO. In a previous study, we addressed the chemistry of carbon (C and C 2 ) with H 2 showing that acetylene

    更新日期:2020-06-01
  • Wandering Massive Black Holes or Analogs of the First Repeating Fast Radio Burst?
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    T. Eftekhari, E. Berger, B. Margalit, B. D. Metzger, and P. K. G. Williams

    The discovery of a persistent radio source coincident with the first repeating fast radio burst, FRB 121102, and offset from the center of its dwarf host galaxy has been used as evidence for a link with young millisecond magnetars born in superluminous supernovae or long-duration gamma-ray bursts (LGRBs). A prediction of this scenario is that compact radio sources offset from the centers of dwarf galaxies

    更新日期:2020-06-01
  • A Deep CFHT Optical Search for a Counterpart to the Possible Neutron Star–Black Hole Merger GW190814
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Nicholas Vieira, John J. Ruan, Daryl Haggard, Maria R. Drout, Melania C. Nynka, Hope Boyce, Kristine Spekkens, Samar Safi-Harb, Raymond G. Carlberg, Rodrigo Fernández, Anthony L. Piro, Niloufar Afsariardchi, and Dae-Sik Moon

    We present a wide-field optical imaging search for electromagnetic counterparts to the likely neutron star–black hole (NS–BH) merger GW190814/S190814bv. This compact binary merger was detected through gravitational waves by the LIGO/Virgo interferometers, with masses suggestive of an NS–BH merger. We imaged the LIGO/Virgo localization region using the MegaCam instrument on the Canada–France–Hawaii

    更新日期:2020-06-01
  • Separating Accretion and Mergers in the Cosmic Growth of Black Holes with X-Ray and Gravitational-wave Observations
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Fabio Pacucci and Abraham Loeb

    Black holes across a broad range of masses play a key role in the evolution of galaxies. The initial seeds of black holes formed at z ∼ 30 and grew over cosmic time by gas accretion and mergers. Using observational data for quasars and theoretical models for the hierarchical assembly of dark matter halos, we study the relative importance of gas accretion and mergers for black hole growth, as a function

    更新日期:2020-06-01
  • GASP XXVII: Gas-phase Metallicity Scaling Relations in Disk Galaxies with and without Ram Pressure Stripping
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Andrea Franchetto, Benedetta Vulcani, Bianca M. Poggianti, Marco Gullieuszik, Matilde Mingozzi, Alessia Moretti, Neven Tomičić, Jacopo Fritz, Daniela Bettoni, and Yara L. Jaffé

    Exploiting the data from the GAs Stripping Phenomena in galaxies with MUSE (GASP) survey, we study the gas-phase metallicity scaling relations of a sample of 29 cluster galaxies undergoing ram pressure stripping and of a reference sample of (16 cluster and 16 field) galaxies with no significant signs of gas disturbance. We adopt the pyqz code to infer the mean gas metallicity at the effective radius

    更新日期:2020-06-01
  • Diffusive Shock Acceleration in N Dimensions
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Assaf Lavi, Ofir Arad, Yotam Nagar, and Uri Keshet

    Collisionless shocks are often studied in two spatial dimensions (2D) to gain insights into the 3D case. We analyze diffusive shock acceleration for an arbitrary number ##IMG## [http://ej.iop.org/images/0004-637X/895/2/107/apjab8d2bieqn1.gif] {$N\in {\mathbb{N}}$} of dimensions. For a nonrelativistic shock of compression ratio ##IMG## [http://ej.iop.org/images/0004-637X/895/2/107/apjab8d2bieqn2.gif]

    更新日期:2020-06-01
  • Galaxy Morphology Network: A Convolutional Neural Network Used to Study Morphology and Quenching in ∼100,000 SDSS and ∼20,000 CANDELS Galaxies
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Aritra Ghosh, C. Megan Urry, Zhengdong Wang, Kevin Schawinski, Dennis Turp, and Meredith C. Powell

    We examine morphology-separated color–mass diagrams to study the quenching of star formation in ∼100,000 ( z ∼ 0) Sloan Digital Sky Survey (SDSS) and ∼20,000 ( z ∼ 1) Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) galaxies. To classify galaxies morphologically, we developed Galaxy Morphology Network (G a M or N et ), a convolutional neural network that classifies galaxies

    更新日期:2020-06-01
  • Star Formation in Massive Galaxies at Redshift z ∼ 0.5
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Kun Xu, Chengze Liu, Yipeng Jing, Yunchong Wang, and Shengdong Lu

    It is believed that massive galaxies have quenched their star formation because of active galactic nucleus feedback. However, recent studies have shown that some massive galaxies are still forming stars. We analyze the morphology of star formation regions for galaxies of stellar masses larger than 10 11.3 M ⊙ at around redshift z r = 0.5 using u − z color images. We find that about 20% of the massive

    更新日期:2020-06-01
  • Counting on Short Gamma-Ray Bursts: Gravitational-wave Constraints of Jet Geometry
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Amanda Farah, Reed Essick, Zoheyr Doctor, Maya Fishbach, and Daniel E. Holz

    The detections of GW170817 and GRB 170817A revealed that at least some short gamma-ray bursts (sGRB) are associated with the merger of neutron-star compact binaries. The gamma-rays are thought to result from the formation of collimated jets, but the details of this process continue to elude us. One important feature of gamma-ray bursts is the emission profile of the jet as a function of viewing angle

    更新日期:2020-06-01
  • Extrapolation of Three-dimensional Magnetic Field Structure in Flare-productive Active Regions with Different Initial Conditions
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Y. Kawabata, S. Inoue, and T. Shimizu

    Nonlinear force-free field (NLFFF) modeling has been extensively used as a tool to infer three-dimensional (3D) magnetic field structure. In this study, the dependency of the NLFFF calculation with respect to the initial guess of the 3D magnetic field is investigated. While major parts of the previous studies used the potential field as the initial guess in NLFFF modeling, we adopt linear force-free

    更新日期:2020-06-01
  • Galactic Cosmic-ray Anisotropies: Electrons Observed by Voyager 1 in the Very Local Interstellar Medium
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    J. S. Rankin, D. J. McComas, and N. A. Schwadron

    Now over seven years into its journey beyond the heliopause, Voyager 1 continues to return unprecedented observations of energetic particles, magnetic fields, and plasma emissions from the very local interstellar medium. Shortly after its heliopause crossing, Voyager 1 discovered an unusual time-varying galactic cosmic-ray anisotropy, characterized by smoothly changing intensity reductions in particles

    更新日期:2020-06-01
  • Correlations between Black Holes and Host Galaxies in the Illustris and IllustrisTNG Simulations
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Yuan Li, Melanie Habouzit, Shy Genel, Rachel Somerville, Bryan A. Terrazas, Eric F. Bell, Annalisa Pillepich, Dylan Nelson, Rainer Weinberger, Vicente Rodriguez-Gomez, Chung-Pei Ma, Ruediger Pakmor, Lars Hernquist, and Mark Vogelsberger

    We study black hole–host galaxy correlations, and the relation between the overmassiveness (the distance from the average M BH – σ relation) of supermassive black holes (SMBHs) and the star formation histories of their host galaxies in the Illustris and TNG100 simulations. We find that both simulations are able to produce black hole scaling relations in general agreement with observations at z = 0

    更新日期:2020-06-01
  • On the Small Contribution of Supermicron Dust Particles to Light Scattering by Comets
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    Evgenij Zubko, Gorden Videen, Jessica A. Arnold, Benjamin MacCall, Alycia J. Weinberger, and Sungsoo S. Kim

    We quantitatively investigate the contribution of large dust particles to the polarimetric response in comets using the light-scattering properties of model agglomerated debris particles. We demonstrate that large, supermicron-sized particles have a decreasing role on the degree of linear polarization at phase angle α ≤ 80°, and the effect of particles greater than 10 μ m is minimal. At larger phase

    更新日期:2020-06-01
  • Individual Estimates of the Virial Factor in 10 Quasars: Implications on the Kinematics of the Broad-line Region
    Astrophys. J.  (IF 5.58) Pub Date : 2020-06-01
    E. Mediavilla, J. Jiménez-vicente, J. Mejía-restrepo, V. Motta, E. Falco, J. A. Muñoz, C. Fian, and E. Guerras

    Assuming a gravitational origin for the Fe iii λλ 2039-2113 redshift and using microlensing based estimates of the size of the region emitting this feature, we obtain individual measurements of the virial factor, f , in 10 quasars. The average values for the Balmer lines, ##IMG## [http://ej.iop.org/images/0004-637X/895/2/111/apjab8ae0ieqn1.gif] {$\langle {f}_{{\rm{H}}\beta }\rangle =0.43\pm 0.20$}

    更新日期:2020-06-01
  • Requirements for Gravitational Collapse in Planetesimal Formation—The Impact of Scales Set by Kelvin–Helmholtz and Nonlinear Streaming Instability
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Konstantin Gerbig, Ruth A. Murray-Clay, Hubert Klahr, and Hans Baehr

    The formation of planetesimals is a challenging problem in planet formation theory. A prominent scenario for overcoming dust growth barriers is the gravitational collapse of locally over-dense regions, shown to robustly produce ∼100 km–sized objects. Still, the conditions under which planetesimal formation occurs remain unclear. For collapse to proceed, the self-gravity of an over-density must overcome

    更新日期:2020-05-31
  • Barred Galaxies in the Illustris-1 and TNG100 Simulations: A Comparison Study
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Ze-Bang Zhou, Weishan Zhu, Yang Wang, and Long-Long Feng

    We carry out a comparison study on the bar structure in the Illustris-1 and TNG100 simulations. At z = 0, 8.9% of 1232 disk galaxies with stellar masses ##IMG## [http://ej.iop.org/images/0004-637X/895/2/92/apjab8d32ieqn1.gif] {$\gt {10}^{10.5}{M}_{\odot }$} in Illustris-1 are barred, while the numbers are 55% of 1269 in TNG100. The bar fraction as a function of stellar mass in TNG100 agrees well with

    更新日期:2020-05-31
  • The Bright Reverse Shock Emission in the Optical Afterglows of Gamma-Ray Bursts in a Stratified Medium
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Shuang-Xi Yi, Xue-Feng Wu, Yuan-Chuan Zou, and Zi-Gao Dai

    The reverse shock (RS) model is generally introduced to interpret the optical afterglows with the rapid rising and decaying, such as the early optical afterglow of GRB 990123 (which is also called the optical flash). In this paper, we collected 11 gamma-ray burst (GRB) early optical afterglows, which have signatures of dominant RS emission. Since the temporal slopes of the optical flashes are determined

    更新日期:2020-05-31
  • Studies in Astronomical Time-series Analysis. VII. An Enquiry Concerning Nonlinearity, the rms–Mean Flux Relation, and Lognormal Flux Distributions
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Jeffrey D. Scargle

    A broad and widely used class of stationary, linear, additive time-series models can have statistical properties that many authors have asserted imply that the underlying process must be nonlinear, nonstationary, multiplicative, or inconsistent with shot noise. This result is demonstrated with exact and numerical evaluation of the model flux distribution function and dependence of flux standard deviation

    更新日期:2020-05-31
  • The Flare-dominated Accretion Mode of a Radio-bright Candidate Transitional Millisecond Pulsar
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Kwan-Lok Li, Jay Strader, James C. A. Miller-Jones, Craig O. Heinke, and Laura Chomiuk

    We report new simultaneous X-ray and radio continuum observations of 3FGL J0427.9−6704, a candidate member of the enigmatic class of transitional millisecond pulsars. These XMM-Newton and Australia Telescope Compact Array observations of this nearly edge-on, eclipsing low-mass X-ray binary were taken in the sub-luminous disk state at an X-ray luminosity of ##IMG## [http://ej.iop.org/images/0004-63

    更新日期:2020-05-31
  • Quasar Microlensing Variability Studies Favor Shallow Accretion Disk Temperature Profiles
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-31
    Matthew A. Cornachione and Christopher W. Morgan

    We compare the microlensing-based continuum emission region size measurements in a sample of 15 gravitationally lensed quasars with estimates of luminosity-based thin disk sizes to constrain the temperature profile of the quasar continuum accretion region. If we adopt the standard thin disk model, we find a significant discrepancy between sizes estimated using the luminosity and those measured by microlensing

    更新日期:2020-05-31
  • Identification of Prebiotic Molecules Containing Peptide-like Bonds in a Hot Molecular Core, G10.47+0.03
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Prasanta Gorai, Bratati Bhat, Milan Sil, Suman K. Mondal, Rana Ghosh, Sandip K. Chakrabarti, and Ankan Das

    After hydrogen, oxygen, and carbon, nitrogen is one of the most chemically active species in the interstellar medium. Nitrogen-bearing molecules are very important as they are actively involved in the formation of biomolecules. Therefore, it is essential to look for nitrogen-bearing species in various astrophysical sources, specifically around high-mass star-forming regions where the evolutionary history

    更新日期:2020-05-27
  • Star Formation Traced by Optical and Millimeter Hydrogen Recombination Lines and Free–Free Emissions in the Dusty Merging Galaxy NGC 3256—MUSE/VLT and ALMA Synergy
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Tomonari Michiyama, Daisuke Iono, Kouichiro Nakanishi, Junko Ueda, Toshiki Saito, Takuji Yamashita, Alberto Bolatto, and Min Yun

    A galaxy–galaxy merger and the subsequent triggering of starburst activity are fundamental processes linked to the morphological transformation of galaxies and the evolution of star formation across the history of the universe. Both nuclear and disk-wide starbursts are assumed to occur during the merger process. However, quantifying both nuclear and disk-wide star formation activity is nontrivial because

    更新日期:2020-05-27
  • The Lazy Giants: APOGEE Abundances Reveal Low Star Formation Efficiencies in the Magellanic Clouds
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    David L. Nidever, Sten Hasselquist, Christian R. Hayes, Keith Hawkins, Joshua Povick, Steven R. Majewski, Verne V. Smith, Borja Anguiano, Guy S. Stringfellow, Jennifer S. Sobeck, Katia Cunha, Timothy C. Beers, Joachim M. Bestenlehner, Roger E. Cohen, D. A. Garcia-Hernandez, Henrik Jönsson, Christian Nitschelm, Matthew Shetrone, Ivan Lacerna, Carlos Allende Prieto, Rachael L. Beaton, Flavia Dell’Agli

    We report the first APOGEE metallicities and α -element abundances measured for 3600 red giant stars spanning a large radial range of both the Large (LMC) and Small Magellanic Clouds, the largest Milky Way (MW) dwarf galaxies. Our sample is an order of magnitude larger than that of previous studies and extends to much larger radial distances. These are the first results presented that make use of the

    更新日期:2020-05-27
  • Measured Optical Absorption Cross Sections of TiO
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Peter Bernath

    A laboratory emission spectrum of TiO in the visible and near-infrared regions (476–1176 nm) has been calibrated and corrected. High-resolution experimental absorption cross sections for TiO with natural isotopic abundance are provided at a temperature of about 2300 K. These cross sections have been compared with those derived from the ExoMol line list. The experimental cross sections can be used directly

    更新日期:2020-05-27
  • COLDz: A High Space Density of Massive Dusty Starburst Galaxies ∼1 Billion Years after the Big Bang
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Dominik A. Riechers, Jacqueline A. Hodge, Riccardo Pavesi, Emanuele Daddi, Roberto Decarli, Rob J. Ivison, Chelsea E. Sharon, Ian Smail, Fabian Walter, Manuel Aravena, Peter L. Capak, Christopher L. Carilli, Pierre Cox, Elisabete da Cunha, Helmut Dannerbauer, Mark Dickinson, Roberto Neri, and Jeff Wagg

    We report the detection of CO( J = 2 → 1) emission from three massive dusty starburst galaxies at z > 5 through molecular line scans in the NSF’s Karl G. Jansky Very Large Array (VLA) CO Luminosity Density at High Redshift (COLDz) survey. Redshifts for two of the sources, HDF 850.1 ( z = 5.183) and AzTEC-3 ( z = 5.298), were previously known. We revise a previous redshift estimate for the third source

    更新日期:2020-05-27
  • Intermittency and Ion Temperature–Anisotropy Instabilities: Simulation and Magnetosheath Observation
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Ramiz A. Qudsi, Riddhi Bandyopadhyay, Bennett A. Maruca, Tulasi N. Parashar, William H. Matthaeus, Alexandros Chasapis, S. Peter Gary, Barbara L. Giles, Daniel J. Gershman, Craig J. Pollock, Robert J. Strangeway, Roy B. Torbert, Thomas E. Moore, and James L. Burch

    Weakly collisional space plasmas are rarely in local thermal equilibrium and often exhibit non-Maxwellian electron and ion velocity distributions that lead to the growth of microinstabilities—that is, enhanced electric and magnetic fields at relatively short wavelengths. These instabilities play an active role in the evolution of space plasmas, as does ubiquitous broadband turbulence induced by turbulent

    更新日期:2020-05-27
  • Super-resolution Imaging of the Protoplanetary Disk HD 142527 Using Sparse Modeling
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Masayuki Yamaguchi, Kazunori Akiyama, Takashi Tsukagoshi, Takayuki Muto, Akimasa Kataoka, Fumie Tazaki, Shiro Ikeda, Misato Fukagawa, Mareki Honma, and Ryohei Kawabe

    With an emphasis on improving the fidelity even in super-resolution regimes, new imaging techniques have been intensively developed over the last several years, which may provide substantial improvements to the interferometric observation of protoplanetary disks. In this study, sparse modeling (SpM) is applied for the first time to observational data sets taken by the Atacama Large Millimeter/submillimeter

    更新日期:2020-05-27
  • Titanium and Iron in the Cassiopeia A Supernova Remnant
    Astrophys. J.  (IF 5.58) Pub Date : 2020-05-27
    Gregory S. Vance, Patrick A. Young, Christopher L. Fryer, and Carola I. Ellinger

    Mixing above the proto-neutron star is believed to play an important role in the supernova engine, and this mixing results in a supernova explosion with asymmetries. Elements produced in the innermost ejecta, e.g., 56 Ni and 44 Ti, provide a clean probe of this engine. The production of 44 Ti is particularly sensitive to the exact production pathway and, by understanding the available pathways, we

    更新日期:2020-05-27
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