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  • Limits on stellar structures in Lovelock theories of gravity
    Phys. Dark Universe (IF 4.473) Pub Date : 2020-07-01
    Sumanta Chakraborty; Naresh Dadhich

    We study the bound on the compactness of a stellar object in pure Lovelock theories of arbitrary order in arbitrary spacetime dimensions, involving electromagnetic field. The bound we derive for a generic pure Lovelock theory, reproduces the known results in four dimensional Einstein gravity. Both the case of a charged shell and that of a charge sphere demonstrates that for a given spacetime dimension

    更新日期:2020-07-02
  • Bardeen stellar structures with Karmarkar condition
    Phys. Dark Universe (IF 4.473) Pub Date : 2020-06-27
    G. Mustafa; M. Farasat Shamir; Mushtaq Ahmad

    This current study is focussed to discuss the existence of a new family of compact star solutions by adopting the Karmarkar condition in the background of Bardeen black hole geometry. For this purpose, we consider static spherically symmetric spacetime with anisotropic fluid distribution in the presence of electric charge. We consider a specific model of grr metric function, to describe a new family

    更新日期:2020-07-02
  • The spin tensor of dark matter and the Hubble parameter tension
    Phys. Dark Universe (IF 4.473) Pub Date : 2020-07-02
    Fernando Izaurieta; Samuel Lepe; Omar Valdivia

    Allowing for a nonvanishing spin tensor for cold dark matter (ωDM=0) has the consequence of giving rise to an effective FLRW dynamics with a small negative barotropic constant for an effective dark matter density (−1∕3<ωeff≤0). This turns out to solve the Hubble parameter tension in a straightforward way.

    更新日期:2020-07-02
  • Anti-de Sitter Hayward black holes in Einstein-Gauss–Bonnet gravity
    Phys. Dark Universe (IF 4.473) Pub Date : 2020-07-02
    Sushant G. Ghosh; Arun Kumar; Dharm Veer Singh

    Lovelock gravitation theory is a natural extension of the General Relativity to higher dimensions with the inclusion of only second-order terms correspond to the Einstein-Gauss–Bonnet gravity. In this paper, we find an exact Hayward black hole solution of D≥5-dimensional spacetime for Einstein-Gauss–Bonnet (EGB) gravity with negative cosmological constant (Λ) minimally coupled to non-linear electrodynamics

    更新日期:2020-07-02
  • f(Q,T) gravity models with observational constraints
    Phys. Dark Universe (IF 4.473) Pub Date : 2020-07-02
    Simran Arora; S.K.J. Pacif; Snehasish Bhattacharjee; P.K. Sahoo

    The paper presents late time cosmology in f(Q,T) gravity where the dark energy is purely geometric in nature. We start by employing a well motivated f(Q,T) gravity model, f(Q,T)=mQn+bT where m,n and b are model parameters. Additionally we also assume the universe to be dominated by pressure-less matter which yields a power law type scale factor of the form a(t)=c2(At+c1)1A, where A=3(8π+b)n(16π+3b)

    更新日期:2020-07-02
  • The bivariate gas–stellar mass distributions and the mass functions of early- and late-type galaxies at $z\,{\sim}\,0$
    Publ. Astron. Soc. Aust. (IF 5.067) Pub Date : 2020-06-19
    Aldo Rodríguez-Puebla; A. R. Calette; Vladimir Avila-Reese; Vicente Rodriguez-Gomez; Marc Huertas-Company

    We report the bivariate $\rm HI$ - and $\rm H_{2}$ -stellar mass distributions of local galaxies in addition of an inventory of galaxy mass functions, MFs, for $\rm HI$ , $\rm H_{2}$ , cold gas, and baryonic mass, separately into early- and late-type galaxies. The MFs are determined using the $\rm HI$ and $\rm H_{2}$ conditional distributions and the galaxy stellar mass function (GSMF). For the conditional

    更新日期:2020-07-02
  • Defeating stochasticity: coalescence timescales of massive black holes in galaxy mergers
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Imran Nasim; Alessia Gualandris; Justin Read; Walter Dehnen; Maxime Delorme; Fabio Antonini

    The coalescence of massive black hole binaries (BHBs) in galactic mergers is the primary source of gravitational waves (GWs) at low frequencies. Current estimates of GW detection rates for the Laser Interferometer Space Antenna and the Pulsar Timing Array vary by three orders of magnitude. To understand this variation, we simulate the merger of equal-mass, eccentric, galaxy pairs with central massive

    更新日期:2020-07-02
  • Broadband Study of High-Synchrotron-Peaked BL Lac Object 1ES 1218+304
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    N Sahakyan

    The origin of the multiwavelength emission from the high-synchrotron-peaked BL Lac 1ES 1218+304 is studied using the data from Swift UVOT/XRT, NuSTAR and Fermi-LAT. A detailed temporal and spectral analysis of the data observed during 2008-2020 in the γ-ray (>100 MeV), X-ray (0.3-70 keV), and optical/UV bands is performed. The γ-ray spectrum is hard with a photon index of 1.71 ± 0.02 above 100 MeV

    更新日期:2020-07-02
  • ALMA observations of CS in NGC 1068: chemistry and excitation
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    M Scourfield; S Viti; S García-Burillo; A Saintonge; F Combes; A Fuente; C Henkel; A Alonso-Herrero; N Harada; S Takano; T Nakajima; S Martín; M Krips; P P van der Werf; S Aalto; A Usero; K Kohno

    We present results from Atacama Large Millimeter/submillimeter Array (ALMA) observations of CS from the nearby galaxy NGC 1068 (∼14 Mpc). This Seyfert 2 barred galaxy possesses a circumnuclear disc (CND, r ∼ 200 pc) and a starburst ring (SB ring, r ∼ 1.3 kpc). These high-resolution maps (∼0.5″, ∼35 pc) allow us to analyse specific sub-regions in the galaxy and investigate differences in line intensity

    更新日期:2020-07-02
  • Gaia white dwarfs within 40 pc I: spectroscopic observations of new candidates
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    P-E Tremblay; M A Hollands; N P Gentile Fusillo; J McCleery; P Izquierdo; B T Gänsicke; E Cukanovaite; D Koester; W R Brown; S Charpinet; T Cunningham; J Farihi; N Giammichele; V van Grootel; J J Hermes; M J Hoskin; S Jordan; S O Kepler; S J Kleinman; C J Manser; T R Marsh; D de Martino; A Nitta; S G Parsons; I Pelisoli; R Raddi; A Rebassa-Mansergas; J-J Ren; M R Schreiber; R Silvotti; O Toloza; S

    We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from Gaia Data Release 2 (DR2) and in almost all cases had no prior spectroscopic classifications. We find a total of 191 confirmed white dwarfs and 39 main-sequence star contaminants. The majority of stellar remnants

    更新日期:2020-07-02
  • Cataloging the radio-sky with unsupervised machine learning: a new approach for the SKA era
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    T J Galvin; M Huynh; R P Norris; X R Wang; E Hopkins; K Polsterer; N O Ralph; A N O’Brien; G H Heald

    We develop a new analysis approach towards identifying related radio components and their corresponding infrared host galaxy based on unsupervised machine learning methods. By exploiting PINK, a self-organising map algorithm, we are able to associate radio and infrared sources without the a priori requirement of training labels. We present an example of this method using 894,415 images from the FIRST

    更新日期:2020-07-02
  • The Ophiuchus DIsc Survey Employing ALMA (ODISEA). II. The effect of stellar multiplicity on disc properties
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Alice Zurlo; Lucas A Cieza; Sebastián Pérez; Valentin Christiaens; Jonathan P Williams; Greta Guidi; Hector Cánovas; Simon Casassus; Antonio Hales; David A Principe; Dary Ruíz-Rodríguez; Antonia Fernandez-Figueroa

    We present Adaptive Optics (AO) near infrared (NIR) observations using VLT/NACO and Keck/NIRC2 of ODISEA targets. ODISEA is an ALMA survey of the entire population of circumstellar discs in the Ophiuchus molecular cloud. From the whole sample of ODISEA we select all the discs that are not already observed in the NIR with AO and that are observable with NACO or NIRC2. The NIR-ODISEA survey consists

    更新日期:2020-07-02
  • The SkyMapper-Gaia RVS view of the Gaia-Enceladus-Sausage – an investigation of the metallicity and mass of the Milky Way’s last major merger
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Diane K Feuillet; Sofia Feltzing; Christian L Sahlholdt; Luca Casagrande

    We characterize the Gaia-Enceladus-Sausage kinematic structure recently discovered in the Galactic halo using photometric metallicities from the SkyMapper survey, and kinematics from Gaia radial velocities measurements. By examining the metallicity distribution functions (MDFs) of stars binned in kinematic/action spaces, we find that the |$\sqrt{J_R}$| vs Lz space allows for the cleanest selection

    更新日期:2020-07-02
  • The ram pressure stripped radio tails of galaxies in the Coma cluster
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Hao Chen; Ming Sun; Masafumi Yagi; Hector Bravo-Alfaro; Elias Brinks; Jeffrey Kenney; Francoise Combes; Suresh Sivanandam; Pavel Jachym; Matteo Fossati; Giuseppe Gavazzi; Alessandro Boselli; Paul Nulsen; Craig Sarazin; Chong Ge; Michitoshi Yoshida; Elke Roediger

    Previous studies have revealed a population of galaxies in galaxy clusters with ram pressure stripped (RPS) tails of gas and embedded young stars. We observed 1.4 GHz continuum and HI emission with the Very Large Array in its B–configuration in two fields of the Coma cluster to study the radio properties of RPS galaxies. The best continuum sensitivities in the two fields are 6 and 8 μJy per 4″ beam

    更新日期:2020-07-02
  • How to tell an accreting boson star from a black hole
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Hector Olivares; Ziri Younsi; Christian M Fromm; Mariafelicia De Laurentis; Oliver Porth; Yosuke Mizuno; Heino Falcke; Michael Kramer; Luciano Rezzolla

    The capability of the Event Horizon Telescope (EHT) to image the nearest supermassive black hole candidates at horizon-scale resolutions offers a novel means to study gravity in its strongest regimes and to test different models for these objects. Here we study the observational appearance at 230 GHz of a surfaceless black hole mimicker, namely a nonrotating boson star, in a scenario consistent with

    更新日期:2020-07-02
  • Can magnetized turbulence set the mass scale of stars?
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Dávid Guszejnov; Michael Y Grudić; Philip F Hopkins; Stella S R Offner; Claude-André Faucher-Giguère

    Understanding the evolution of self-gravitating, isothermal, magnetized gas is crucial for star formation, as these physical processes have been postulated to set the initial mass function (IMF). We present a suite of isothermal magnetohydrodynamic (MHD) simulations using the GIZMO code, that follow the formation of individual stars in giant molecular clouds (GMCs), spanning a range of Mach numbers

    更新日期:2020-07-02
  • Near Mean Motion Resonance of Terrestrial Planet Pair Induced by Giant Planet: Application to Kepler-68 System
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Mengrui Pan; Su Wang; Jianghui Ji

    In this work, we investigate configuration formation of two inner terrestrial planets near mean motion resonance (MMRs) induced by the perturbation of a distant gas-giant for the Kepler-68 system, by conducting thousands of numerical simulations. The results show that the formation of terrestrial planets is relevant to the speed of Type I migration, the mass of planets, and the existence of giant planet

    更新日期:2020-07-02
  • Centroid frequency ratios of simultaneous low-frequency QPOs in black hole low-mass X-ray binaries
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Marieke van Doesburgh; Michiel van der Klis

    We measure the centroid frequency ratios of simultaneous QPOs that occur at low frequency (0.1–30 Hz) in a selection of accreting BH LMXBs. We use all data in the RXTE archive on GX 339−4, GRO J1655−40, 4U 1630−47, XTE J1550−564 and H 1743−322. We select the power spectra that show at least two simultaneous QPOs, and empirically divide them into four main categories, whose occurrence correlates systematically

    更新日期:2020-07-02
  • Forecast constraints on Anisotropic Stress in Dark Energy using gravitational-waves
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Weiqiang Yang; Supriya Pan; David F Mota; Minghui Du

    It is always interesting to investigate how well can a future experiment perform with respect to others (present or future ones). Cosmology is really an exciting field where a lot of puzzles are still unknown. In this article we consider a generalized dark energy (DE) scenario where anisotropic stress is present. We constrain this generalized cosmic scenario with an aim to investigate how gravitational

    更新日期:2020-07-02
  • A random-walk model for dark matter halo spins
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Andrew Benson; Christoph Behrens; Yu Lu

    We extend the random-walk model of Vitvitska et al. for predicting the spins of dark matter halos from their merger histories. Using updated merger rates, orbital parameter distributions, and N-body constraints we show that this model can accurately reproduce the distribution of spin parameters measured in N-body simulations when we include a weak correlation between the spins of halos and the angular

    更新日期:2020-07-02
  • Gravitation in terms of observables 2: the algebra of fundamental observables
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Rodolfo Gambini, Saeed Rastgoo and Jorge Pullin

    In a previous paper, we showed how to use the techniques of the group of loops to formulate the loop approach to gravity proposed by Mandelstam in the 1960’s. Those techniques allow to overcome some of the difficulties that had been encountered in the earlier treatment. In this approach, gravity is formulated entirely in terms of Dirac observables without constraints, opening attractive new possibilities

    更新日期:2020-07-02
  • Horseshoe Co-orbitals of Earth: Current Population and New Candidates
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Murat Kaplan; Sergen Cengiz

    Most co-orbital objects in the Solar system are thought to follow tadpole-type orbits, behaving as Trojans. However, most of Earth’s identified co-orbitals are moving along horseshoe-type orbits. The current tally of minor bodies considered to be Earth co-orbitals amounts to 18; of them, 12 are horseshoes, five are quasi-satellites, and one is a Trojan. The semimajor axis values of all these bodies

    更新日期:2020-07-02
  • Gravitational anomalies in nAdS 2 /nCFT 1
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Alejandra Castro and Beatrix Mühlmann

    We revisit the holographic description of the near horizon geometry of the BTZ black hole in AdS 3 gravity, with a gravitational Chern–Simons term included. After a dimensional reduction of the three dimensional theory, we use the framework of nAdS 2 /nCFT 1 to describe the near horizon physics. This setup allows us to contrast the role of the gravitational and conformal anomaly inherited from AdS

    更新日期:2020-07-02
  • Collins in Wonderland
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Ben David Normann and Sigbjørn Hervik

    What is the asymptotic future of a scalar-field model if the assumption of isotropy is relaxed in generic, homogeneous Universe models? This paper is a continuation of our previous work on Bianchi cosmologies with a p -form field (where p ∈ {1, 3})—or equivalently: an inhomogeneous, mass-less scalar gauge field with a homogeneous gradient. In this work we investigate such matter sector in general relativity

    更新日期:2020-07-02
  • Probing massive scalar fields from a pulsar in a stellar triple system
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Brian C Seymour and Kent Yagi

    Pulsar timing observations precisely test general relativity. Recently, the hierarchical triple system PSR J0337 + 1715 has placed new constraints on the existence of a fifth force from violation in the strong equivalence principle. Many alternative gravity theories exist with massive (pseudo-)scalar fields to explain a variety of phenomena from the accelerating expansion of the Universe at large scales

    更新日期:2020-07-02
  • More on dual actions for massive spin-2 particles
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    D Dalmazi and A L R dos Santos

    Here we start from a dual version of Vasiliev’s first order action for massless spin-2 particles (linearized first order Einstein–Hilbert) and derive, via Kaluza–Klein dimensional reduction from D + 1 to D dimensions, a set of dual massive spin-2 models. This set includes the massive ‘BR’ model, a spin-2 analogue of the spin-1 Cremmer–Scherk model. In our approach the linearized Riemann curvature emerges

    更新日期:2020-07-02
  • Generalized Vaidya solutions in bimetric gravity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Marcus Högås, Mikica Kocic, Francesco Torsello and Edvard Mörtsell

    In general relativity, the endpoint of spherically symmetric gravitational collapse is a Schwarzschild–[(A)dS] black hole. In bimetric gravity, it has been speculated that a static end state must also be Schwarzschild–[(A)dS]. To this end, we present a set of exact solutions, including collapsing massless dust particles. For these, the speculation is confirmed.

    更新日期:2020-07-02
  • Hamilton–Jacobi approach for Regge–Teitelboim cosmology
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Alejandro Aguilar-Salas, Alberto Molgado and Efraín Rojas

    The Hamilton–Jacobi formalism for a geodetic brane-like Universe described by the Regge–Teitelboim model is developed. We focus on the description of the complete set of Hamiltonians that ensure the integrability of the model in addition to obtaining the Hamilton principal function S . In order to do this, we avoid the second-order in derivative nature of the model by appropriately defining a set of

    更新日期:2020-07-02
  • Rotating five-dimensional electrically charged Bardeen regular black holes
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Muhammed Amir, Md Sabir Ali and Sunil D Maharaj

    We derive a rotating counterpart of the five-dimensional electrically charged Bardeen regular black holes spacetime by employing the Giampieri algorithm on static one. The associated nonlinear electrodynamics source is computed in order to justify the rotating solution. We thoroughly discuss the energy conditions and the other properties of the rotating spacetime. The black hole thermodynamics of the

    更新日期:2020-07-02
  • Detection of glyceraldehyde and glycerol in VUV processed interstellar ice analogues containing formaldehyde: a general formation route for sugars and polyols
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Y Layssac; A Gutiérrez-Quintanilla; T Chiavassa; F Duvernay

    Complex organic molecules (COMs) have been identified toward high -and low- mass protostars as well as molecular clouds. Among them sugar-like and polyol two carbon-bearing molecules such as glycolaldehyde and ethylene glycol are of special interest. Recent laboratory experiments have shown that they can efficiently be formed via atom addition reactions between accreting H-atoms and CO molecules or

    更新日期:2020-07-02
  • Spin Parity of Spiral Galaxies II: A catalogue of 80k spiral galaxies using big data from the Subaru Hyper Suprime-Cam Survey and deep learning
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Ken-ichi Tadaki; Masanori Iye; Hideya Fukumoto; Masao Hayashi; Cristian E Rusu; Rhythm Shimakawa; Tomoka Tosaki

    We report an automated morphological classification of galaxies into S-wise spirals, Z-wise spirals, and non-spirals using big image data taken from Subaru/Hyper Suprime-Cam (HSC) Survey and a convolutional neural network(CNN)-based deep learning technique. The HSC i-band images are about 25 times deeper than those from the Sloan Digital Sky Survey (SDSS) and have a two times higher spatial resolution

    更新日期:2020-07-02
  • New insight into the origin of the GeV flare in the binary system PSR B1259-63 / LS 2883 from the 2017 periastron passage.
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    M Chernyakova; D Malyshev; S Mc Keague; B van Soelen; J P Marais; A Martin-Carrillo; D Murphy

    PSR B1259-63is a gamma-ray binary system hosting a radio pulsar orbiting around a O9.5Ve star, LS 2883, with a period of ∼ 3.4 years. The interaction of the pulsar wind with the LS 2883 outflow leads to unpulsed broad band emission in the radio, X-rays, GeV and TeV domains. While the radio, X-ray and TeV light curves show rather similar behaviour, the GeV light curve appears very different with a huge

    更新日期:2020-07-02
  • Simplified 3D GCM modelling of the irradiated brown dwarf WD0137-349B
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-02
    Graham K H Lee; Sarah L Casewell; Katy L Chubb; Mark Hammond; Xianyu Tan; Shang-Min Tsai; Raymond T Pierrehumbert

    White dwarf - Brown dwarf short period binaries (Porb ≲ 2 hours) are some of the most extreme irradiated atmospheric environments known. These systems offer an opportunity to explore theoretical and modelling efforts of irradiated atmospheres different to typical hot Jupiter systems. We aim to investigate the three dimensional atmospheric structural and dynamical properties of the Brown dwarf WD0137-349B

    更新日期:2020-07-02
  • Thermal luminosities of cooling neutron stars
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    A Y Potekhin; D A Zyuzin; D G Yakovlev; M V Beznogov; Yu A Shibanov

    Ages and thermal luminosities of neutron stars, inferred from observations, can be interpreted with the aid of the neutron star cooling theory to gain information on the properties of superdense matter in neutron-star interiors. We present a survey of estimated ages, surface temperatures and thermal luminosities of middle-aged neutron stars with relatively weak or moderately strong magnetic fields

    更新日期:2020-07-02
  • Thermally Unstable Cooling Stimulated by Uplift: The Spoiler Clusters
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    C. G. Martz, B. R. McNamara, P. E. J. Nulsen, A. N. Vantyghem, M-J. Gingras, Iu. V. Babyk, H. R. Russell, A.  C. Edge, M. McDonald, P. D. Tamhane, A. C. Fabian, and M. T. Hogan

    Chandra X-ray observations are analyzed for five galaxy clusters whose atmospheric cooling times, entropy parameters, and ratios of cooling time to freefall time within the central galaxies lie below 1 Gyr, below 30 keV cm 2 , and between 20 ≲ min( t cool / t ff ) ≲ 50, respectively. These thermodynamic properties are commonly associated with molecular clouds, bright H α emission, and star formation

    更新日期:2020-07-02
  • Cradle(s) of the Sun
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Susanne Pfalzner and Kirsten Vincke

    The Sun likely formed as part of a group of stars. A close stellar flyby by one of the solar siblings is probably responsible for the sharp outer edge in the solar system's mass distribution. The frequency of such close flybys can be used to determine the likely type of birth environment of the solar system. Young stellar groups develop very quickly, expanding significantly within just a few million

    更新日期:2020-07-02
  • Orbital and Mass Constraints of the Young Binary System IRAS 16293-2422 A
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    María José Maureira, Jaime E. Pineda, Dominique M. Segura-Cox, Paola Caselli, Leonardo Testi, Giuseppe Lodato, Laurent Loinard, and Antonio Hernández-Gómez

    We present 3 mm ALMA continuum and line observations at resolutions of 6.5 au and 13 au, respectively, toward the Class 0 system IRAS 16293-2422 A. The continuum observations reveal two compact sources toward IRAS 16293-2422 A, coinciding with compact ionized gas emission previously observed at radio wavelengths (A1 and A2), confirming the long-known radio sources as protostellar. The emission toward

    更新日期:2020-07-02
  • The Variable and Non-variable X-Ray Absorbers in Compton-thin Type II Active Galactic Nuclei
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Sibasish Laha, Alex G. Markowitz, Mirko Krumpe, Robert Nikutta, Richard Rothschild, and Tathagata Saha

    We have conducted an extensive X-ray spectral variability study of a sample of 20 Compton-thin type II galaxies using broadband spectra from XMM-Newton, Chandra, and Suzaku. The aim is to study the variability of the neutral intrinsic X-ray obscuration along the line of sight and investigate the properties and location of the dominant component of the X-ray-obscuring gas. The observations are sensitive

    更新日期:2020-07-02
  • Planes of Satellites around Simulated Disk Galaxies. I. Finding High-quality Planar Configurations from Positional Information and Their Comparison to MW/M31 Data
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Isabel Santos-Santos, Rosa Domínguez-Tenreiro, Héctor Artal, Susana E. Pedrosa, Lucas Bignone, Francisco Martínez-Serrano, M. Ángeles Gómez-Flechoso, Patricia B. Tissera, and Arturo Serna

    We address the “plane of satellites problem” by studying planar configurations around two disk galaxies with no late major mergers, formed in zoom-in hydro-simulations. Due to the current lack of good-quality kinematic data for M31 satellites, we use only positional information. So far, positional analyses of simulations are unable to find planes as thin and populated as the observed ones. We follow

    更新日期:2020-07-02
  • The Warm–Hot, Extended, Massive Circumgalactic Medium of NGC 3221: An XMM-Newton Discovery
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Sanskriti Das, Smita Mathur, and Anjali Gupta

    Using Suzaku data, we had found a 3.4 σ evidence for the X-ray emitting warm–hot circumgalactic medium (CGM) in the L ⋆ galaxy NGC 3221. Here we present XMM-Newton data and outline an efficient, rigorous, and well-defined method to extract the faint CGM signal. We confirm the CGM detection at 4 σ significance within 30–200 kpc of the galaxy. We claim with 99.62% confidence that the CGM is extended

    更新日期:2020-07-02
  • Coherent Stellar Motion in Galactic Spiral Arms by Swing Amplification
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Shugo Michikoshi and Eiichiro Kokubo

    We perform local N -body simulations of disk galaxies and investigate the evolution of spiral arms. We calculate the time autocorrelation of the surface density of spiral arms and find that the typical evolution timescale is described by the epicycle period. We investigate the distribution of the orbital elements of stars and find that in spiral arms the epicycle motions of stars are in phase while

    更新日期:2020-07-02
  • The X-ray View of Merger-Induced AGN Activity at Low Redshift
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Nathan J Secrest; Sara L Ellison; Shobita Satyapal; Laura Blecha

    Galaxy mergers are predicted to trigger accretion onto the central supermassive black holes, with the highest rates occurring during final coalescence. Previously, we have shown elevated rates of both optical and mid-IR selected active galactic nuclei (AGN) in post-mergers, but to date the prevalence of X-ray AGN has not been examined in the same systematic way. We present XMM-Newton data of 43 post-merger

    更新日期:2020-07-02
  • The Spin-period History of Intermediate Polars
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Joseph Patterson, Enrique de Miguel, Jonathan Kemp, Shawn Dvorak, Berto Monard, Franz-Josef Hambsch, Tonny Vanmunster, David R. Skillman, David Cejudo, Tut Campbell, George Roberts, Jim Jones, Lewis M. Cook, Greg Bolt, Robert Rea, Joseph Ulowetz, Thomas Krajci, Kenneth Menzies, Simon Lowther, William Goff, William Stein, Matt A. Wood, Gordon Myers, Geoffrey Stone, Helena Uthas, Emir Karamehmetoglu

    We report the detailed history of spin-period changes in five intermediate polars (DQ Herculis, AO Piscium, FO Aquarii, V1223 Sagittarii, and BG Canis Minoris) during the 30–60 yr since their original discovery. Most are slowly spinning up, although there are sometimes years-long episodes of spin-down. This is supportive of the idea that the underlying magnetic white dwarfs are near spin equilibrium

    更新日期:2020-07-02
  • Solar Filaments and Interplanetary Magnetic Field B z
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    V. Aparna and Petrus C. Martens

    The direction of the axis of an interplanetary coronal mass ejection (ICME) plays an important role in determining if it will cause a geomagnetic disturbance in the Earth’s magnetosphere upon impact. Long period southward-pointing ICME fields are known to cause significant space weather impacts and thus geomagnetic storms. We present an extensive analysis of CME–ICME directionality using 86 halo-CMEs

    更新日期:2020-07-02
  • Implications of Inhomogeneous Metal Mixing for Stellar Archaeology
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Yuta Tarumi, Tilman Hartwig, and Mattis Magg

    The first supernovae enrich the previously pristine gas with metals, out of which the next generation of stars form. Based on hydrodynamical simulations, we develop a new stochastic model to predict the metallicity of star-forming gas in the first galaxies. On average, in internally enriched galaxies, the metals are well mixed with the pristine gas. However, in externally enriched galaxies, the metals

    更新日期:2020-07-02
  • Element Stratification in the Middle-aged SN Ia Remnant G344.7–0.1
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Kotaro Fukushima, Hiroya Yamaguchi, Patrick O. Slane, Sangwook Park, Satoru Katsuda, Hidetoshi Sano, Laura A. Lopez, Paul P. Plucinsky, Shogo B. Kobayashi, and Kyoko Matsushita

    Despite their importance, a detailed understanding of Type Ia supernovae (SNe Ia) remains elusive. X-ray measurements of the element distributions in supernova remnants (SNRs) offer important clues for understanding the explosion and nucleosynthesis mechanisms for SNe Ia. However, it is challenging to observe the entire ejecta mass in X-rays for young SNRs, because the central ejecta may not have been

    更新日期:2020-07-02
  • The Role of Turbulence for Heating Plasmas in Eruptive Solar Flares
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Jing Ye, Qiangwei Cai, Chengcai Shen, John C. Raymond, Jun Lin, Ilia. I. Roussev, and Zhixing Mei

    Magnetohydrodynamic turbulence is ubiquitous in the process of solar eruptions, and it is crucial for the fast release of energy and the formation of complex thermal structures that have been found in observations. In this paper, we focus on the turbulence in two specific regions: inside the current sheet (CS) and above the flare loops, considering the standard flare model. The gravitationally stratified

    更新日期:2020-07-02
  • Accurate Treatment of Comptonization in X-Ray Illuminated Accretion Disks
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Javier A. García, Ekaterina Sokolova-Lapa, Thomas Dauser, Jerzy Madej, Agata Różańska, Agnieszka Majczyna, Fiona A. Harrison, and Jörn Wilms

    A large fraction of accreting black hole and neutron star systems present clear evidence of the reprocessing of X-rays in the atmosphere of an optically thick accretion disk. The main hallmarks of X-ray reflection include fluorescent K-shell emission lines from iron (∼6.4–6.9 keV), the absorption iron K-edge (∼7–9 keV), and a broad featureless component known as the Compton hump (∼20–40 keV). This

    更新日期:2020-07-02
  • Orphan GRB Afterglow Searches with the Pan-STARRS1 COSMOS Survey
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Yun-Jing Huang, Yuji Urata, Kuiyun Huang, Kuei-sheng Lee, Meng-feng Tsai, Yuji Shirasaki, Marcin Sawicki, Stephane Arnouts, Thibaud Moutard, Stephen Gwyn, Wei-Hao Wang, Sebastien Foucaud, Keiichi Asada, Mark E. Huber, Richard Wainscoat, and Kenneth C. Chambers

    We present the result of a search for orphan gamma-ray burst (GRB) afterglows in the Pan-STARRS1 (PS1) COSMOS survey. There is extensive theoretical and observational evidence suggesting that GRBs are collimated jets; the direct observation of orphan GRB afterglows would further support this model. An optimal survey strategy is designed by coupling the PS1 survey with the Subaru/Hyper-Suprime-Cam (HSC)

    更新日期:2020-07-02
  • The Local Star Formation Rate Surface Density and Metallicity Relation for Star-forming Galaxies
    Astrophys. J.  (IF 5.745) Pub Date : 2020-07-01
    Berzaf Berhane Teklu, Yulong Gao, Xu Kong, Zesen Lin, and Zhixiong Liang

    We study the relations between gas-phase metallicity ( Z ), local stellar mass surface density (Σ * ), and the local star formation surface density (Σ SFR ) in a sample of 1120 star-forming galaxies from the MaNGA survey. At fixed Σ * the local metallicity increases as Σ SFR decreases or vice versa for metallicity calibrators of N2 and O3N2. Alternatively, at fixed Σ SFR metallicity increases as Σ

    更新日期:2020-07-02
  • Cooling of hybrid neutron stars with microscopic equations of state
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    J-B Wei; G F Burgio; H-J Schulze; D Zappalà

    We model the cooling of hybrid neutron stars combining a microscopic nuclear equation of state in the Brueckner-Hartree-Fock approach with different quark models. We then analyze the neutron star cooling curves predicted by the different models and single out the preferred ones. We find that the possibility of neutron p-wave pairing can be excluded in our scenario.

    更新日期:2020-07-02
  • Wide binaries are rare in open clusters
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    N R Deacon; A L Kraus

    The population statistics of binary stars are an important output of star formation models. However populations of wide binaries evolve over time due to interactions within a system’s birth environment and the unfolding of wide, hierarchical triple systems. Hence the wide binary populations observed in star forming regions or OB associations may not accurately reflect the wide binary populations that

    更新日期:2020-07-02
  • Shape Analysis of H ii Regions – II. Synthetic Observations
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Justyn Campbell-White; Ahmad A Ali; Dirk Froebrich; Alfred Kume

    The statistical shape analysis method developed for probing the link between physical parameters and morphologies of Galactic H ii regions is applied here to a set of synthetic observations (SOs) of a numerically modelled H ii region. The systematic extraction of H ii region shape, presented in the first paper of this series, allows for a quantifiable confirmation of the accuracy of the numerical simulation

    更新日期:2020-07-02
  • Relativistic, Axisymmetric, Viscous, Radiation Hydrodynamic Simulations of Geometrically Thin Disks. II. Disk Variability
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Bhupendra Mishra; Wlodek Kluźniak; P Chris Fragile

    An analysis of two-dimensional viscous, radiation hydrodynamic numerical simulations of thin α-disks around a stellar mass black hole reveals multiple robust, coherent oscillations. Our disk models are initialized on both the gas- and radiation-pressure-dominated branches of the thermal equilibrium curve, with mass accretion rates between |$\dot{M} = 0.01 L_\mathrm{Edd}/c^2$| and 10 LEdd/c2. In the

    更新日期:2020-07-02
  • Progenitor, Precursor and Evolution of the Dusty Remnant of the Stellar Merger M31-LRN-2015
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    N Blagorodnova; V Karambelkar; S M Adams; M M Kasliwal; C S Kochanek; S Dong; H Campbell; S Hodgkin; J E Jencson; J Johansson; S Kozłowski; R R Laher; F Masci; P Nugent; U Rebbapragada

    M31-LRN-2015 is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. Archival data shows that the source started to brighten ∼2 years before the nova event. During this precursor phase, the source brightened by ∼3 mag. The lightcurve at 6 and 1.5 months before the main outburst may show periodicity

    更新日期:2020-07-02
  • ExoMol line lists – XXXIX. Ro-vibrational molecular line list for CO2
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    S N Yurchenko; Thomas M Mellor; Richard S Freedman; J Tennyson

    A new hot line list for the main isotopologue of CO2, 12C16O2 is presented. The line list consists of almost 2.5 billion transitions between 3.5 million rotation-vibration states of CO2 in its ground electronic state, covering the wavenumber range 0–20 000 cm−1 (λ > 0.5 μm) with the upper and lower energy thresholds of 36 000 cm−1 and 16 000 cm−1, respectively. The ro-vibrational energies and wavefunctions

    更新日期:2020-07-02
  • Forecasting seeing for the maunakea observatories
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Ryan Lyman; Tiziana Cherubini; Steven Businger

    Optical turbulence greatly impacts the range and quality of astronomical observations. Advanced knowledge of the expected atmospheric optical turbulence provides important guidance that helps astronomers decide which instrument to schedule and enables them to optimize the adaptive optics technology that improves image resolution. Along with forecasts of weather conditions, prediction of the optical

    更新日期:2020-07-02
  • Dust Settling Instability in Protoplanetary Discs
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Leonardo Krapp; Andrew N Youdin; Kaitlin M Kratter; Pablo Benítez-Llambay

    The streaming instability (SI) has been extensively studied in the linear and non-linear regimes as a mechanism to concentrate solids and trigger planetesimal formation in the midplane of protoplanetary discs. A related dust settling instability (DSI) applies to particles while settling towards the midplane. The DSI has previously been studied in the linear regime, with predictions that it could trigger

    更新日期:2020-07-02
  • Quantification of the expected residual dispersion of the MICADO Near-IR imaging instrument
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    J A van den Born; W Jellema

    MICADO, a near-infrared imager for the Extremely Large Telescope, is being designed to deliver diffraction limited imaging and 50 micro arcsecond (µas) astrometric accuracy. MICADO employs an atmospheric dispersion corrector (ADC) to keep the chromatic elongation of the point spread function (PSF) under control. We must understand the dispersion and residuals after correction to reach the optimum performance

    更新日期:2020-07-02
  • Extended cuscuton as dark energy
    J. Cosmol. Astropart. Phys. (IF 5.21) Pub Date : 2020-07-01
    Aya Iyonaga, Kazufumi Takahashi and Tsutomu Kobayashi

    Late-time cosmology in the extended cuscuton theory is studied, in which gravity is modified while one still has no extra dynamical degrees of freedom other than two tensor modes. We present a simple example admitting analytic solutions for the cosmological background evolution that mimics ΛCDM cosmology. We argue that the extended cuscuton as dark energy can be constrained, like usual scalar-tensor

    更新日期:2020-07-02
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