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  • Stellar X-Ray Activity Across the Hertzsprung–Russell Diagram. I. Catalogs
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Song Wang, Yu Bai, Lin He, and Jifeng Liu

    Stellar magnetic activity provides substantial information on the magnetic dynamo and the coronal heating process. We present a catalog of X-ray activity for about 6000 stars, based on the Chandra and Gaia DR2 data. We also classified more than 3000 stars as young stellar objects, dwarf stars, or giant stars. By using the stars with valid stellar parameters and classifications, we studied the distribution

    更新日期:2020-10-19
  • The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Multiband Constraints on Line-luminosity Functions and the Cosmic Density of Molecular Gas
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Roberto Decarli, Manuel Aravena, Leindert Boogaard, Chris Carilli, Jorge González-López, Fabian Walter, Paulo C. Cortes, Pierre Cox, Elisabete da Cunha, Emanuele Daddi, Tanio Díaz-Santos, Jacqueline A. Hodge, Hanae Inami, Marcel Neeleman, Mladen Novak, Pascal Oesch, Gergö Popping, Dominik Riechers, Ian Smail, Bade Uzgil, Paul van der Werf, Jeff Wagg, and Axel Weiss

    We present a CO and atomic fine-structure line-luminosity function analysis using the ALMA Spectroscopic Survey (ASPECS) in the Hubble Ultra Deep Field. ASPECS consists of two spatially overlapping mosaics that cover the entire ALMA 3 mm and 1.2 mm bands. We combine the results of a line-candidate search of the 1.2 mm data cube with those previously obtained from the 3 mm cube. Our analysis shows that

    更新日期:2020-10-19
  • Exploring the Chemistry Induced by Energetic Processing of the H2-bearing, CO-rich Apolar Ice Layer
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Rafael Martín-Doménech, Pavlo Maksiutenko, Karin I. Öberg, and Mahesh Rajappan

    Interstellar ice mantles on the surfaces of dust grains are thought to have a bilayered structure, with a H 2 O-rich polar layer, covered by a CO-rich apolar layer that probably harbors H 2 and other volatiles such as N 2 . In this work, we explore the chemistry induced by 2 keV electrons and Ly α photons in H 2 :CO: 15 N 2 ice analogs of the CO-rich layer when exposed to similar fluences to those

    更新日期:2020-10-19
  • The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Constraining the Molecular Content at log( M * / M ⊙ ) ∼ 9.5 with CO Stacking of MUSE-detected z ∼ 1.5 Galaxies
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Hanae Inami, Roberto Decarli, Fabian Walter, Axel Weiss, Chris Carilli, Manuel Aravena, Leindert Boogaard, Jorge Gonzaĺez-López, Gergö Popping, Elisabete da Cunha, Roland Bacon, Franz Bauer, Thierry Contini, Paulo C. Cortes, Pierre Cox, Emanuele Daddi, Tanio Díaz-Santos, Melanie Kaasinen, Dominik A. Riechers, Jeff Wagg, Paul van der Werf, and Lutz Wisotzki

    We report molecular gas mass estimates obtained from a stacking analysis of CO line emission in the ALMA Spectroscopic Survey (ASPECS) using the spectroscopic redshifts from the optical integral field spectroscopic survey by the Multi Unit Spectroscopic Explorer (MUSE) of the Hubble Ultra Deep Field (HUDF). Stacking was performed on subsets of the sample of galaxies classified by their stellar mass

    更新日期:2020-10-19
  • EvryFlare. III. Temperature Evolution and Habitability Impacts of Dozens of Superflares Observed Simultaneously by Evryscope and TESS
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff, Nathan Galliher, Amy L. Glazier, Ramses Gonzalez, Alan Vasquez Soto, Octavi Fors, Daniel del Ser, and Joshua Haislip

    Superflares may provide the dominant source of biologically relevant UV radiation to rocky habitable-zone M-dwarf planets (M-Earths), altering planetary atmospheres and conditions for surface life. The combined line and continuum flare emission has usually been approximated by a 9000 K blackbody. If superflares are hotter, then the UV emission may be 10 times higher than predicted from the optical

    更新日期:2020-10-19
  • The Mean Absorption-line Spectra of a Selection of Luminous z ∼ 6 Lyman Break Galaxies
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Yuichi Harikane, Nicolas Laporte, Richard S. Ellis, and Yoshiki Matsuoka

    We examine the absorption-line spectra of a sample of 31 luminous ( ##IMG## [http://ej.iop.org/images/0004-637X/902/2/117/apjabb597ieqn1.gif] {${M}_{\mathrm{UV}}\simeq -23$} ) Lyman break galaxies at redshift z ≃ 6 using data taken with the FOCAS and OSIRIS spectrographs on the Subaru and GTC telescopes. For two of these sources we present longer exposure data taken at higher spectral resolutions from

    更新日期:2020-10-19
  • A Survey of 3–5.4 μ m Emission from Planetary Nebulae Using SOFIA/FLITECAM
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Erin C. Smith, Sarah E. Logsdon, Ian S. McLean, Elizabeth Fletcher, William D. Vacca, E. E. Becklin, Sachindev Shenoy, Maureen Savage, and Ryan T. Hamilton

    Here we present the results of an airborne 3–5.4 μ m spectroscopic study of three young, carbon-rich planetary nebulae (PNs) IC 5117, PNG 093.9-00.1, and BD +30 3639. These observations were made using the grism spectroscopy mode of the First Light Infrared TEst CAMera (FLITECAM) instrument during airborne science operations on board NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA).

    更新日期:2020-10-19
  • The ALMA Spectroscopic Survey Large Program: The Infrared Excess of z = 1.5–10 UV-selected Galaxies and the Implied High-redshift Star Formation History
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Rychard Bouwens, Jorge González-López, Manuel Aravena, Roberto Decarli, Mladen Novak, Mauro Stefanon, Fabian Walter, Leindert Boogaard, Chris Carilli, Ugnė Dudzevičiūtė, Ian Smail, Emanuele Daddi, Elisabete da Cunha, Rob Ivison, Themiya Nanayakkara, Paulo Cortes, Pierre Cox, Hanae Inami, Pascal Oesch, Gergö Popping, Dominik Riechers, Paul van der Werf, Axel Weiss, Yoshi Fudamoto, and Jeff Wagg

    We make use of sensitive (9.3 μ Jy beam −1 rms) 1.2 mm continuum observations from the Atacama Large Millimeter/submillimeter Array (ALMA) Spectroscopic Survey in the Hubble Ultra-Deep Field (ASPECS) large program to probe dust-enshrouded star formation from 1362 Lyman-break galaxies spanning the redshift range z = 1.5–10 (to ∼7–28 M ⊙ yr −1 at 4 σ over the entire range). We find that the fraction

    更新日期:2020-10-19
  • The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: CO Excitation and Atomic Carbon in Star-forming Galaxies at z = 1–3
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Leindert A. Boogaard, Paul van der Werf, Axel Weiss, Gergö Popping, Roberto Decarli, Fabian Walter, Manuel Aravena, Rychard Bouwens, Dominik Riechers, Jorge González-López, Ian Smail, Chris Carilli, Melanie Kaasinen, Emanuele Daddi, Pierre Cox, Tanio Díaz-Santos, Hanae Inami, Paulo C. Cortes, and Jeff Wagg

    We investigate the CO excitation and interstellar medium (ISM) conditions in a cold gas mass-selected sample of 22 star-forming galaxies at z = 0.46–3.60, observed as part of the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field (ASPECS). Combined with Very Large Array follow-up observations, we detect a total of 34 CO ##IMG## [http://ej.iop.org/images/0004-637X/902/2/109/apjabb82fieqn1.gif]

    更新日期:2020-10-19
  • The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-18
    Fabian Walter, Chris Carilli, Marcel Neeleman, Roberto Decarli, Gergö Popping, Rachel S. Somerville, Manuel Aravena, Frank Bertoldi, Leindert Boogaard, Pierre Cox, Elisabete da Cunha, Benjamin Magnelli, Danail Obreschkow, Dominik Riechers, Hans-Walter Rix, Ian Smail, Axel Weiss, Roberto J. Assef, Franz Bauer, Rychard Bouwens, Thierry Contini, Paulo C. Cortes, Emanuele Daddi, Tanio Diaz-Santos, Jorge

    We combine the recent determination of the evolution of the cosmic density of molecular gas (H 2 ) using deep, volumetric surveys, with previous estimates of the cosmic density of stellar mass, star formation rate and atomic gas (H i ), to constrain the evolution of baryons associated with galaxies averaged over cosmic time and space. The cosmic H i and H 2 densities are roughly equal at z ∼ 1.5. The

    更新日期:2020-10-19
  • The Hidden Past of M92: Detection and Characterization of a Newly Formed 17° Long Stellar Stream Using the Canada–France Imaging Survey
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Guillaume F. Thomas, Jaclyn Jensen, Alan McConnachie, Patrick Côté, Kim Venn, Nicolas Longeard, Raymond Carlberg, Scott Chapman, Jean-Charles Cuillandre, Benoit Famaey, Laura Ferrarese, Stephen Gwyn, François Hammer, Rodrigo A. Ibata, Khyati Malhan, Nicolas F. Martin, Simona Mei, Julio F. Navarro, Céline Reylé, and Else Starkenburg

    We present an analysis of the structure, kinematics, and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a “color–color–magnitude” diagram, created using photometry from the Canada–France Imaging Survey and the Pan-STARRS 1 3 π survey. We find the stream to have a length

    更新日期:2020-10-16
  • Hydrodynamical Modeling of the Light Curves of Core-collapse Supernovae with HYPERION. I. The Mass Range 13–25 M ⊙ , the Metallicities −3 ≤ [Fe/H] ≤ 0, and the Case of SN 1999em
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Marco Limongi and Alessandro Chieffi

    We present the last version of HYdrodynamic Ppm Explosion with Radiation diffusION ( Hyperion ), a hydrodynamic code designed to calculate the explosive nucleosynthesis, remnant mass, and light curve associated with the explosion of a massive star. By means of this code, we compute the explosion of a subset of red supergiant models taken from the database published by Limongi & Chieffi for various

    更新日期:2020-10-16
  • Two Modes of Carbonaceous Dust Alignment
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    A. Lazarian

    Radiative torques (RATs) or mechanical torques acting on irregular grains can induce the alignment of dust grains in respect to the alignment axis (AA), which can be either the direction of the magnetic field or the direction of the radiation. We show that carbonaceous grains can be aligned with their axes both parallel and perpendicular to the AA, and we explore the conditions where the particular

    更新日期:2020-10-16
  • Evidence for and Analysis of Multiple Hidden Coronal Strands in Cross-sectional Emission Profiles: Further Results from NASA’s High-resolution Solar Coronal Imager
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Thomas Williams, Robert W. Walsh, Hardi Peter, and Amy R. Winebarger

    Previous work utilizing NASA’s High-resolution Coronal Imager (Hi-C 2.1) 172 Å observations revealed that, even at the increased spatial scales available in the dataset, there may be evidence for coronal structures that are still not fully resolved. In this follow-up study, cross-section slices of coronal strands are taken across the Hi-C 2.1 field of view. Following previous loop-width studies, the

    更新日期:2020-10-16
  • Rotation Curves in z ∼ 1–2 Star-forming Disks: Evidence for Cored Dark Matter Distributions
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    R. Genzel, S. H. Price, H. Übler, N. M. Förster Schreiber, T. T. Shimizu, L. J. Tacconi, R. Bender, A. Burkert, A. Contursi, R. Coogan, R. L. Davies, R. I. Davies, A. Dekel, R. Herrera-Camus, M.-J. Lee, D. Lutz, T. Naab, R. Neri, A. Nestor, A. Renzini, R. Saglia, K. Schuster, A. Sternberg, E. Wisnioski, and S. Wuyts

    We report high-quality, H α or CO rotation curves (RCs) to several R e for 41 large, massive, star-forming disk galaxies (SFGs) across the peak of cosmic galaxy evolution ( z ∼ 0.67–2.45), taken with the ESO-VLT, the LBT and IRAM-NOEMA. Most RC41 SFGs have reflection-symmetric RCs plausibly described by equilibrium dynamics. We fit the major axis position–velocity cuts using beam-convolved forward

    更新日期:2020-10-16
  • ALMA 0.″02 Resolution Observations Reveal HCN-abundance-enhanced Counter-rotating and Outflowing Dense Molecular Gas at the NGC 1068 Nucleus
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Masatoshi Imanishi, Dieu D. Nguyen, Keiichi Wada, Yoshiaki Hagiwara, Satoru Iguchi, Takuma Izumi, Nozomu Kawakatu, Kouichiro Nakanishi, and Kyoko Onishi

    We present ALMA ∼0.″02 resolution observations of the nucleus of the nearby (∼14 Mpc) type 2 active galactic nucleus NGC 1068 at HCN/HCO + /HNC J = 3–2 lines, as well as at their 13 C isotopologue and vibrationally excited lines, to scrutinize the morphological, dynamical, chemical, and physical properties of dense molecular gas in the putative dusty molecular torus around a mass-accreting supermassive

    更新日期:2020-10-16
  • A Theory for the Maximum Magnitude versus Rate of Decline Relation of Classical Novae
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Izumi Hachisu, Hideyuki Saio, Mariko Kato, Martin Henze, and Allen W. Shafter

    We propose a theory for the maximum magnitude versus rate of decline (MMRD) relation of novae using free–free emission model light curves built on the optically thick wind theory. We calculated ##IMG## [http://ej.iop.org/images/0004-637X/902/2/91/apjabb5faieqn1.gif] {$({t}_{3},{M}_{V,\max })$} for various sets of ##IMG## [http://ej.iop.org/images/0004-637X/902/2/91/apjabb5faieqn2.gif] {$({\dot{M}}_{\mathrm{acc}}

    更新日期:2020-10-16
  • Multi-gigayear White Dwarf Cooling Delays from Clustering-enhanced Gravitational Sedimentation
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Evan B. Bauer, Josiah Schwab, Lars Bildsten, and Sihao Cheng

    Cooling white dwarfs (WDs) can yield accurate ages when theoretical cooling models fully account for the physics of the dense plasma of WD interiors. We use MESA to investigate cooling models for a set of massive and ultramassive WDs (0.9–1.3 ##IMG## [http://ej.iop.org/images/0004-637X/902/2/93/apjabb5a5ieqn1.gif] {${M}_{\odot }$} ) for which previous models have failed to match kinematic age indicators

    更新日期:2020-10-16
  • EVR-CB-004: An Inflated Hot Subdwarf O Star + Unseen WD Companion in a Compact Binary Discovered with the Evryscope
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    Jeffrey K. Ratzloff, Thomas Kupfer, Brad N. Barlow, David Schneider, Thomas R. Marsh, Ulrich Heber, Kyle A. Corcoran, Evan Bauer, Steven Hämmerich, Henry T. Corbett, Amy Glazier, Ward S. Howard, and Nicholas M. Law

    We present the discovery of EVR-CB-004, a close binary with a remnant stellar core and an unseen white dwarf (WD) companion. The analysis in this work reveals that the primary is potentially an inflated hot subdwarf (sdO) and more likely is a rarer post–blue horizontal branch (post-BHB) star. Post-BHBs are the short-lived shell-burning final stage of a blue horizontal star or hot subdwarf before transitioning

    更新日期:2020-10-16
  • A Multiwavelength Study of PSR J1119–6127 after 2016 Outburst
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    H.-H. Wang, L. C.-C. Lin, S. Dai, J. Takata, K. L. Li, C.-P. Hu, and X. Hou

    The high magnetic field pulsar PSR J1119−6127, detected from radio to high-energy wavelengths, underwent a magnetar-like outburst beginning on 2016 July 27. In this paper, we study the postoutburst multiwavelength properties of this pulsar from the radio to GeV bands and discuss its similarity with the outburst of the magnetar XTE J1810−197. In phase-resolved spectral analysis of 0.5–10 keV X-ray data

    更新日期:2020-10-16
  • Shear-driven Transition to Isotropically Turbulent Solar Wind Outside the Alfvén Critical Zone
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-14
    D. Ruffolo, W. H. Matthaeus, R. Chhiber, A. V. Usmanov, Y. Yang, R. Bandyopadhyay, T. N. Parashar, M. L. Goldstein, C. E. DeForest, M. Wan, A. Chasapis, B. A. Maruca, M. Velli, and J. C. Kasper

    Motivated by prior remote observations of a transition from striated solar coronal structures to more isotropic “flocculated” fluctuations, we propose that the dynamics of the inner solar wind just outside the Alfvén critical zone, and in the vicinity of the first ##IMG## [http://ej.iop.org/images/0004-637X/902/2/94/apjabb594ieqn1.gif] {$\beta =1$} surface, is powered by the relative velocities of

    更新日期:2020-10-16
  • Comprehensive Analysis of Magnetospheric Gaps around Kerr Black Holes Using 1D GRPIC Simulations
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Shota Kisaka, Amir Levinson, and Kenji Toma

    Spark gaps are likely the source of plasma in active black hole (BH) magnetospheres. In this paper, we present results of 1D general relativistic particle-in-cell simulations of a starved BH magnetosphere with a realistic treatment of inverse-Compton scattering and pair production, for a broad range of conditions, run times longer than in previous studies, and different setups. We find that following

    更新日期:2020-10-15
  • The CaFe Project: Optical Fe ii and Near-infrared Ca ii Triplet Emission in Active Galaxies. I. Photoionization Modeling
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Swayamtrupta Panda, Mary Loli Martínez-Aldama, Murilo Marinello, Bożena Czerny, Paola Marziani, and Deborah Dultzin

    Optical Fe ii emission is a strong feature in quasar spectra originating in the broad-line region (BLR). The difficulty in understanding the complex Fe ii pseudo-continuum has led us to search for other reliable, simpler ionic species such as Ca ii . In this first part of the series, we confirm the strong correlation between the strengths of two emission features, the optical Fe ii and the NIR Ca ii

    更新日期:2020-10-15
  • Pulsation-driven Mass Loss from Massive Stars behind Stellar Mergers in Metal-poor Dense Clusters
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Daisuke Nakauchi, Kohei Inayoshi, and Kazuyuki Omukai

    The recent discovery of high-redshift ( z > 6) supermassive black holes (SMBH) favors the formation of massive seed BHs in protogalaxies. One possible scenario is the formation of massive stars ##IMG## [http://ej.iop.org/images/0004-637X/902/1/81/apjabb463ieqn1.gif] {$\simeq {10}^{3}\mbox{--}{10}^{4}\,{M}_{\odot }$} via runaway stellar collisions in a dense cluster, leaving behind massive BHs without

    更新日期:2020-10-15
  • A Late-time Radio Survey of Short Gamma-ray Bursts at z < 0.5: New Constraints on the Remnants of Neutron-star Mergers
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Genevieve Schroeder, Ben Margalit, Wen-fai Fong, Brian D. Metzger, Peter K. G. Williams, Kerry Paterson, Kate D. Alexander, Tanmoy Laskar, Armaan V. Goyal, and Edo Berger

    Massive, rapidly spinning magnetar remnants produced as a result of binary neutron-star (BNS) mergers may deposit a fraction of their energy into the surrounding kilonova ejecta, powering a synchrotron radio signal from the interaction of the ejecta with the circumburst medium. Here, we present 6.0 GHz Very Large Array (VLA) observations of nine, low-redshift short gamma-ray bursts (GRBs; z < 0.5)

    更新日期:2020-10-15
  • The Complete Redshift Distribution of Dusty Star-forming Galaxies from the SPT-SZ Survey
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    C. Reuter, J. D. Vieira, J. S. Spilker, A. Weiss, M. Aravena, M. Archipley, M. Béthermin, S. C. Chapman, C. De Breuck, C. Dong, W. B. Everett, J. Fu, T. R. Greve, C. C. Hayward, R. Hill, Y. Hezaveh, S. Jarugula, K. Litke, M. Malkan, D. P. Marrone, D. Narayanan, K. A. Phadke, A. A. Stark, and M. L. Strandet

    The South Pole Telescope (SPT) has systematically identified 81 high-redshift, strongly gravitationally lensed, dusty star-forming galaxies (DSFGs) in a 2500 square degree cosmological millimeter-wave survey. We present the final spectroscopic redshift survey of this flux-limited ( S 870 μ m > 25 mJy) sample, initially selected at 1.4 mm. The redshift survey was conducted with the Atacama Large Mi

    更新日期:2020-10-15
  • Characteristic Mass in Galaxy Quenching: Environmental versus Internal Effects
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Pengfei Li, Huiyuan Wang, H. J. Mo, Enci Wang, and Hui Hong

    A clear transition feature of galaxy quenching is identified in the multi-parameter space of stellar mass ( M * ), bulge-to-total mass ratio ( B / T m ), halo mass ( M h ) and halo-centric distance ( r / r 180 ). For a given halo mass, the characteristic stellar mass ( ##IMG## [http://ej.iop.org/images/0004-637X/902/1/75/apjabb66cieqn1.gif] {${M}_{* ,\mathrm{ch}}$} ) for the transition is about one-fifth

    更新日期:2020-10-15
  • Hydrodynamic Winds from Twin-star Binaries
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Morgan MacLeod and Abraham Loeb

    Stellar winds shape the evolution of stars through the loss of mass. In binary systems, they also shape the stars’ evolution by modifying the orbit. In this paper, we use hydrodynamic simulations to study the emergence of nearly isothermal winds from identical twin binaries. We vary the degree to which model stars fill their Roche lobes and the temperature of the wind. Initialized at rest on the stellar

    更新日期:2020-10-15
  • Space Telescope and Optical Reverberation Mapping Project. XII. Broad-line Region Modeling of NGC 5548
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    P. R. Williams, A. Pancoast, T. Treu, B. J. Brewer, B. M. Peterson, A. J. Barth, M. A. Malkan, G. De Rosa, Keith Horne, G. A. Kriss, N. Arav, M. C. Bentz, E. M. Cackett, E. Dalla Bontà, M. Dehghanian, C. Done, G. J. Ferland, C. J. Grier, J. Kaastra, E. Kara, C. S. Kochanek, S. Mathur, M. Mehdipour, R. W. Pogge, D. Proga, M. Vestergaard, T. Waters, S. M. Adams, M. D. Anderson, P. Arévalo, T. G. Beatty

    We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the H β , C iv , and Ly α broad emission lines. We find an extended disk-like H β BLR with a mixture of near-circular and outflowing gas

    更新日期:2020-10-15
  • CANDELS Meets GSWLC: Evolution of the Relationship between Morphology and Star Formation Since z = 2
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Chandler Osborne, Samir Salim, Ivana Damjanov, S. M. Faber, Marc Huertas-Company, David C. Koo, Kameswara Bharadwaj Mantha, Daniel H. McIntosh, Joel R. Primack, and Sandro Tacchella

    Galaxy morphology and its evolution over the cosmic epoch hold important clues for understanding the regulation of star formation (SF). However, studying the relationship between morphology and SF has been hindered by the availability of consistent data at different redshifts. Our sample, combining CANDELS(0.8 < z < 2.5) and the GALEX-SDSS-WISE Legacy Catalog (GSWLC; z ∼ 0), has physical parameters

    更新日期:2020-10-15
  • Incompleteness Matters Not: Inference of H 0 from Binary Black Hole–Galaxy Cross-correlations
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Sayantani Bera, Divya Rana, Surhud More, and Sukanta Bose

    We show how the angular clustering between gravitational-wave (GW) standard sirens and galaxies with known redshifts allows an inference of the Hubble constant regardless of whether the host galaxies of any of these sirens are present in the galaxy catalog. We demonstrate this for the first time with realistic simulations of GW signals from binary black holes in a three-detector network with Advanced

    更新日期:2020-10-15
  • On the Scaling Properties of Magnetic-field Fluctuations through the Inner Heliosphere
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Tommaso Alberti, Monica Laurenza, Giuseppe Consolini, Anna Milillo, Maria Federica Marcucci, Vincenzo Carbone, and Stuart D. Bale

    Although the interplanetary magnetic-field variability has been extensively investigated in situ using data from several space missions, newly launched missions providing high-resolution measures and approaching the Sun offer the possibility to study the multiscale variability in the innermost solar system. Here, using Parker Solar Probe measurements, we investigate the scaling properties of solar

    更新日期:2020-10-15
  • SN 2020bvc: A Broad-line Type Ic Supernova with a Double-peaked Optical Light Curve and a Luminous X-Ray and Radio Counterpart
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Anna Y. Q. Ho, S. R. Kulkarni, Daniel A. Perley, S. Bradley Cenko, Alessandra Corsi, Steve Schulze, Ragnhild Lunnan, Jesper Sollerman, Avishay Gal-Yam, Shreya Anand, Cristina Barbarino, Eric C. Bellm, Rachel J. Bruch, Eric Burns, Kishalay De, Richard Dekany, Alexandre Delacroix, Dmitry A. Duev, Dmitry D. Frederiks, Christoffer Fremling, Daniel A. Goldstein, V. Zach Golkhou, Matthew J. Graham, David

    We present optical, radio, and X-ray observations of SN 2020bvc (=ASASSN-20bs, ZTF 20aalxlis), a nearby ( ##IMG## [http://ej.iop.org/images/0004-637X/902/1/86/apjaba630ieqn1.gif] {$z=0.0252;$} d = 114 Mpc) broad-line (BL) Type Ic supernova (SN) and the first double-peaked Ic-BL discovered without a gamma-ray burst (GRB) trigger. Our observations show that SN 2020bvc shares several properties in common

    更新日期:2020-10-15
  • The Jet Structure and the Intrinsic Luminosity Function of Short Gamma-Ray Bursts
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-13
    Wei-Wei Tan and Yun-Wei Yu

    The joint observation of GW170817 and GRB 170817A indicated that short gamma-ray bursts (SGRBs) can originate from binary neutron star mergers. Moreover, some SGRBs could be detected off axis, while the SGRB jets are highly structured. Then, by assuming a universal angular distribution of the jet emission for all SGRBs, we reproduce the flux and redshift distributions of the cosmological SGRBs detected

    更新日期:2020-10-15
  • Full Transport General Relativistic Radiation Magnetohydrodynamics for Nucleosynthesis in Collapsars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Jonah M. Miller, Trevor M. Sprouse, Christopher L. Fryer, Benjamin R. Ryan, Joshua C. Dolence, Matthew R. Mumpower, and Rebecca Surman

    We model a compact black hole-accretion disk system in the collapsar scenario with full transport, frequency dependent, general relativistic radiation magnetohydrodynamics. We examine whether or not winds from a collapsar disk can undergo rapid neutron capture (r-process) nucleosynthesis and significantly contribute to solar r-process abundances. We find the inclusion of accurate transport has significant

    更新日期:2020-10-13
  • Starspot Mapping with Adaptive Parallel Tempering. I. Implementation of Computational Code
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Kai Ikuta, Hiroyuki Maehara, Yuta Notsu, Kosuke Namekata, Taichi Kato, Shota Notsu, Soshi Okamoto, Satoshi Honda, Daisaku Nogami, and Kazunari Shibata

    Starspots are thought to be regions of locally strong magnetic fields, similar to sunspots, and they can generate photometric brightness modulations. To deduce stellar and spot properties, such as spot emergence and decay rates, we implement a computational code for starspot modeling. It is implemented with an adaptive parallel tempering algorithm and an importance sampling algorithm for parameter

    更新日期:2020-10-13
  • Electron-impact Excitation of Fe i
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Andrew T. Conroy, Connor P. Ballance, Catherine A. Ramsbottom, and Francis P. Keenan

    The Fe i spectra emitted by astrophysical sources contain information on plasma parameters such as chemical abundances and magnetic fields. However, to determine these parameters requires detailed plasma modeling, which in turn needs accurate atomic data for processes such as radiative decay and electron-impact excitation in Fe i . A lack of fine-structure resolved collision strengths for transitions

    更新日期:2020-10-13
  • On the Rotation of the Solar Chromosphere
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Jing-Chen Xu, Peng-Xin Gao, and Xiang-Jun Shi

    Rotation is a significant characteristic of the Sun and other stars, and it plays an important role in understanding their dynamo actions and magnetic activities. In this study, the rotation of the solar chromospheric activity is investigated from a global point of view with an over 40 yr Mg ii index. We determined the time-varying rotational period lengths (RPLs) with the synchrosqueezed wavelet transform

    更新日期:2020-10-13
  • A QPO in NGC 4945 from Archival RXTE Data
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Evan Smith, Rebecca Robles, and Eric Perlman

    We report the discovery of an ∼6 week quasi-periodic oscillation (QPO) in archival NGC 4945 data observed by the Rossi X-ray Timing Explorer (RXTE) satellite. QPOs are important observables in accretion disks and have been studied extensively in both neutron star (NS) and black hole (BH) X-ray binaries (XRB). QPOs should be present in active galactic nuclei (AGN) if galactic BHs and supermassive black

    更新日期:2020-10-13
  • Localization of Compact Binary Sources with Second-generation Gravitational-wave Interferometer Networks
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Chris Pankow, Monica Rizzo, Kaushik Rao, Christopher P L Berry, and Vassiliki Kalogera

    GW170817 began gravitational-wave multimessenger astronomy. However, GW170817 will not be representative of detections in the coming years because typical gravitational-wave sources will be closer the detection horizon, have larger localization regions, and (when present) will have correspondingly weaker electromagnetic emission. In its design state, the gravitational-wave detector network in the mid-2020s

    更新日期:2020-10-13
  • A New Approach for the Regression of the Center Coordinates and Radius of the Solar Disk Using a Deep Convolutional Neural Network
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Gaofei Zhu, Ganghua Lin, Dongguang Wang, and Xiao Yang

    This paper presents a new approach for the regression of the center coordinates and radius of the solar disk in H α solar full-disk images by using a Deep Convolutional Neural Network. We use ∼100,000 original H α solar full-disk images obtained from Huairou Solar Observing Station as the experimental data set. The data set includes two parts: the original image and three numeric values (center coordinates

    更新日期:2020-10-13
  • Diagonal Ridge Pattern of Different Age Populations Found in Gaia-DR2 with LAMOST Main-sequence Turnoff and OB-type Stars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    H.-F. Wang, Y. Huang, H.-W. Zhang, M. López-Corredoira, W.-Y. Cui, B.-Q. Chen, R. Guo, and J. Chang

    We revisit the diagonal ridge feature (diagonal distributions in the R , v ϕ plane) found in Gaia and present a timing analysis for it between Galactocentric distances of R = 7.5 and 12 kpc, using main-sequence turnoff and OB stars selected from the LAMOST Galactic spectroscopic surveys. We recover the ridge pattern in the R – v ϕ plane color coded by mean radial velocity and find that this feature

    更新日期:2020-10-13
  • On the Impact of Random Residual Calibration Error on the Gibbs ILC CMB Estimates over Large Angular Scales
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Vipin Sudevan and Rajib Saha

    Residual errors in calibration coefficients corresponding to observed cosmic microwave background (CMB) maps are an important issue when estimating a pure CMB signal. These errors in the input-foreground-contaminated CMB maps, if not properly taken into account in a component separation method, may lead to bias in the cleaned CMB map and estimated CMB angular power spectrum. But the inability to exactly

    更新日期:2020-10-13
  • Convectively Driven 3D Turbulence in Massive Star Envelopes. I. A 1D Implementation of Diffusive Radiative Transport
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    William C. Schultz, Lars Bildsten, and Yan-Fei Jiang

    Massive ( M > 30 M ⊙ ) stars exhibit luminosities that are near the Eddington limit for electron scattering, causing the increase in opacity associated with iron at ##IMG## [http://ej.iop.org/images/0004-637X/902/1/67/apjabb405ieqn1.gif] {$T\,\approx 180,000\,{\rm{K}}$} to trigger supersonic convection in their outer envelopes. Three-dimensional radiative hydrodynamics simulations by Jiang and collaborators

    更新日期:2020-10-13
  • Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-12
    Meridith Joyce, Shing-Chi Leung, László Molnár, Michael Ireland, Chiaki Kobayashi, and Ken’ichi Nomoto

    We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observational results include the release of new, processed photometric measurements collected with the space-based Solar Mass Ejection Imager instrument prior to Betelgeuse’s recent, unprecedented dimming event. We detect the first

    更新日期:2020-10-13
  • Supernova Interaction with a Dense Detached Shell in SN 2001em
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Poonam Chandra, Roger A. Chevalier, Nikolai Chugai, Dan Milisavljevic, and Claes Fransson

    We carry out a comprehensive analysis of supernova SN 2001em covering a period of 19 yr since discovery. SN 2001em is the oldest supernova known to have undergone a metamorphosis from a stripped envelope to an interacting supernova. An early spectrum indicates it exploded as a Type Ib supernova. Later, the ejecta caught up with a dense circumstellar H-shell, ejected a few thousand years before the

    更新日期:2020-10-12
  • Mapping the Escape Fraction of Ionizing Photons Using Resolved Stars: A Much Higher Escape Fraction for NGC 4214
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Yumi Choi, Julianne J. Dalcanton, Benjamin F. Williams, Evan D. Skillman, Morgan Fouesneau, Karl D. Gordon, Karin M. Sandstrom, Daniel R. Weisz, and Karoline M. Gilbert

    We demonstrate a new method for measuring the escape fraction of ionizing photons using Hubble Space Telescope imaging of resolved stars in NGC 4214, a local analog of high-redshift starburst galaxies that are thought to be responsible for cosmic reionization. Specifically, we forward model the UV through near-IR spectral energy distributions of ∼83,000 resolved stars to infer their individual ionizing

    更新日期:2020-10-12
  • Revisiting the Complex Nuclear Region of NGC 6240 with Chandra
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    G. Fabbiano, A. Paggi, M. Karovska, M. Elvis, E. Nardini, and Junfeng Wang

    We present a reanalysis of the cumulative ACIS-S Chandra data set pointed at the double active galactic nuclei (AGNs) of the NGC 6240 merging galaxy, focusing on the hard energy bands containing the hard spectral continuum (5.5–5.9 keV), the redshifted Fe i K α line (6.0–6.4 keV), and the redshifted Fe xxv line (6.4–6.7 keV). We have used the full Chandra telescope angular resolution and modeled the

    更新日期:2020-10-12
  • Elemental Abundances in M31: Properties of the Inner Stellar Halo
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Ivanna Escala, Evan N. Kirby, Karoline M. Gilbert, Jennifer Wojno, Emily C. Cunningham, and Puragra Guhathakurta

    We present measurements of [Fe/H] and [ α /Fe] for 128 individual red giant branch stars (RGB) in the stellar halo of M31, including its Giant Stellar Stream (GSS), obtained using spectral synthesis of low- and medium-resolution Keck/DEIMOS spectroscopy ( ##IMG## [http://ej.iop.org/images/0004-637X/902/1/51/apjabb474ieqn1.gif] {$R\sim 3000$} and 6000, respectively). We observed four fields in M31's

    更新日期:2020-10-12
  • The Cosmic Thermal History Probed by Sunyaev–Zeldovich Effect Tomography
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Yi-Kuan Chiang, Ryu Makiya, Brice Ménard, and Eiichiro Komatsu

    The cosmic thermal history, quantified by the evolution of the mean thermal energy density in the universe, is driven by the growth of structures as baryons get shock heated in collapsing dark matter halos. This process can be probed by redshift-dependent amplitudes of the thermal Sunyaev–Zeldovich (SZ) effect background. To do so, we cross-correlate eight sky intensity maps in the Planck and Infrared

    更新日期:2020-10-12
  • Two Flares with One Shock: The Interesting Case of 3C 454.3
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    I. Liodakis, D. Blinov, S. G. Jorstad, A. A. Arkharov, A. Di Paola, N. V. Efimova, T. S. Grishina, S. Kiehlmann, E. N. Kopatskaya, V. M. Larionov, L. V. Larionova, E. G. Larionova, A. P. Marscher, D. A. Morozova, A. A. Nikiforova, V. Pavlidou, E. Traianou, Yu. V. Troitskaya, I. S. Troitsky, M. Uemura, and Z. R. Weaver

    The quasar 3C 454.3 is a blazar known for its rapid and violent outbursts seen across the electromagnetic spectrum. Using γ -ray, X-ray, multiband optical, and very-long-baseline interferometric data we investigate the nature of two such events that occurred in 2013 and 2014 accompanied by strong variations in optical polarization, including a ∼230° electric vector position angle (EVPA) rotation. Our

    更新日期:2020-10-12
  • Local Simulations of Heating Torques on a Luminous Body in an Accretion Disk
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Amelia M. Hankla, Yan-Fei Jiang, and Philip J. Armitage

    A luminous body embedded in an accretion disk can generate asymmetric density perturbations that lead to a net torque and thus orbital migration of the body. Linear theory has shown that this heating torque gives rise to a migration term linear in the body’s mass that can oppose or even reverse that arising from the sum of gravitational Lindblad and co-orbital torques. We use high-resolution local

    更新日期:2020-10-12
  • ALMA CO Observations of Gamma-Ray Supernova Remnant N132D in the Large Magellanic Cloud: Possible Evidence for Shocked Molecular Clouds Illuminated by Cosmic-Ray Protons
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    H. Sano, P. P. Plucinsky, A. Bamba, P. Sharda, M. D. Filipović, C. J. Law, R. Z. E. Alsaberi, Y. Yamane, K. Tokuda, F. Acero, M. Sasaki, J. Vink, T. Inoue, S. Inutsuka, J. Shimoda, K. Tsuge, K. Fujii, F. Voisin, N. Maxted, G. Rowell, T. Onishi, A. Kawamura, N. Mizuno, H. Yamamoto, K. Tachihara, and Y. Fukui

    N132D is the brightest gamma-ray supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out 12 CO( J = 1–0, 3–2) observations toward the SNR using the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Submillimeter Telescope Experiment. We find diffuse CO emission not only at the southern edge of the SNR as previously known, but also inside the X-ray shell. We spatially

    更新日期:2020-10-12
  • Extracting the Possible Intrinsic Relation between the Radiative Efficiency and Mass of QSOs: A Maximum Likelihood Method and its Application to the SDSS DR7 QSOs
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Fupeng Zhang and Youjun Lu

    Radiative efficiencies of QSOs and their distribution encode rich information on the evolution of both masses and spins of massive black holes (MBHs) across cosmic time. In this paper, we develop a maximum likelihood method to statistically extract the intrinsic relation between radiative efficiency ( ϵ ) and mass ( M • ) of QSOs from their distribution on the luminosity–(empirically estimated virial)

    更新日期:2020-10-12
  • A New Transition Wolf–Rayet WN/C Star in the Milky Way
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Wei Zhang, Helge Todt, Hong Wu, Jianrong Shi, Chih-Hao Hsia, Yuzhong Wu, Chaojian Wu, Yongheng Zhao, Tianmeng Zhang, and Yonghui Hou

    We report the discovery of a new transition type Wolf–Rayet (W-R) WN/C star in the Galaxy. According to its coordinates (R.A., decl.) J2000 = ##IMG## [http://ej.iop.org/images/0004-637X/902/1/62/apjabb0e7ieqn1.gif] {${18}^{{\rm{h}}}{51}^{{\rm{m}}}39\buildrel{\rm{s}}\over{.} 7$} , −05°34′51.″1, and the distance (7.11 ##IMG## [http://ej.iop.org/images/0004-637X/902/1/62/apjabb0e7ieqn2.gif] {${}_{-1.22}^{+1

    更新日期:2020-10-12
  • Absorption-line Environments of High-redshift BOSS Quasars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Chen Chen, Fred Hamann, Bo Ma, Britt Lundgren, Donald York, Daniel Nestor, and Yusra AlSayyad

    The early stage of massive galaxy evolution often involves outflows driven by a starburst or a central quasar plus cold mode accretion (infall), which adds to the mass build-up in the galaxies. To study the nature of these infall and outflows in the quasar environments, we have examined the correlation of narrow absorption lines (NALs) at positive and negative velocity shifts to other quasar properties

    更新日期:2020-10-12
  • Star Formation and Morphological Properties of Galaxies in the Pan-STARRS 3 π Survey. I. A Machine-learning Approach to Galaxy and Supernova Classification
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    A. Baldeschi, A. Miller, M. Stroh, R. Margutti, and D. L. Coppejans

    We present a classification of galaxies in the Pan-STARRS1 (PS1) 3 π survey based on their recent star formation history and morphology. Specifically, we train and test two Random Forest (RF) classifiers using photometric features (colors and moments) from the PS1 data release 2. The labels for the morphological classification are taken from Huertas-Company et al., while labels for the star formation

    更新日期:2020-10-12
  • Electron Temperature Anisotropy and Electron Beam Constraints from Electron Kinetic Instabilities in the Solar Wind
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Heyu Sun, Jinsong Zhao, Wen Liu, Huasheng Xie, and Dejin Wu

    Electron temperature anisotropies and electron beams are nonthermal features of the observed nonequilibrium electron velocity distributions in the solar wind. In collision-poor plasmas these nonequilibrium distributions are expected to be regulated by kinetic instabilities through wave–particle interactions. This study considers electron instabilities driven by the interplay of core electron temperature

    更新日期:2020-10-12
  • Evidence for Emergent Dark Energy
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-11
    Xiaolei Li and Arman Shafieloo

    We introduce a generalized form of an emergent dark energy model with one degree of freedom for the dark energy sector that has the flexibility to include both the ΛCDM model as well as the Phenomenologically Emergent Dark Energy (PEDE) model proposed by Li & Shafieloo as two of its special limits. The free parameter for the dark energy sector, namely Δ, has a value of 0 for the Λ case and a value

    更新日期:2020-10-12
  • Effects of Supernova Redshift Uncertainties on the Determination of Cosmological Parameters
    Astrophys. J.  (IF 5.745) Pub Date : 2020-10-07
    Charles L. Steinhardt, Albert Sneppen, and Bidisha Sen

    Redshifts used in current cosmological supernova samples are measured using two primary techniques, one based on well-measured host galaxy spectral lines and the other based on supernova-dominated spectra. Here, we construct an updated Pantheon catalog with revised redshifts, redshift sources, and estimated uncertainties for the entire sample to investigate whether these two techniques yield consistent

    更新日期:2020-10-08
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