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  • 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
  • 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
  • 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
  • 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
  • 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
  • Mapping road traffic crash hotspots using GIS-based methods: A case study of Muscat Governorate in the Sultanate of Oman
    Spat. Stat. (IF 1.656) Pub Date : 2020-07-02
    Amira K. Al-Aamri; Graeme Hornby; Li-Chun Zhang; Abdullah A. Al-Maniri; Sabu S. Padmadas

    Objective: Road traffic crashes (RTCs) are a major global public health problem and cause substantial burden on national economy and healthcare. There is little systematic understanding of the geography of RTCs and the spatial correlations of RTCs in the Middle-East region, particularly in Oman where RTCs are the leading cause of disability-adjusted life years lost. The overarching goal of this paper

    更新日期:2020-07-02
  • A simplification of rigorous atmospheric raytracing based on judicious rectilinear paths for near-surface GNSS reflectometry
    Earth Planets Space (IF 2.075) Pub Date : 2020-07-02
    Thalia Nikolaidou, Marcelo Santos, Simon D. P. Williams, Felipe Geremia-Nievinski

    Atmospheric delays are known to cause biases in Global Navigation Satellite System Reflectometry (GNSS-R) altimetry applications, such as for sea-level monitoring. The main quantity of interest is the reflection-minus-direct or interferometric atmospheric delay. Recently, we have presented a rigorous raytracing procedure to account for linear and angular refraction in conjunction with reflection as

    更新日期:2020-07-02
  • Estimation of fault models for short-term slow slip events from groundwater pressure in soft sedimentary layers
    Earth Planets Space (IF 2.075) Pub Date : 2020-07-02
    Yuichi Kitagawa, Norio Matsumoto, Takeshi Kimura

    Deep low-frequency tremors and short-term slow slip events (SSEs) are known to occur along the Nankai Trough in Japan. Although short-term SSEs are thought to occur repeatedly in the northern part of Ise Bay, deep low-frequency tremors are not observed there. Because the area around the northern part of Ise Bay is characterized by soft sedimentary layers not suitable for strainmeter or tiltmeter installation

    更新日期:2020-07-02
  • Performance estimate of some prototypes of inertial platform and strapdown marine gravimeters
    Earth Planets Space (IF 2.075) Pub Date : 2020-07-02
    Yuan Yuan, Jinyao Gao, Zhaocai Wu, Zhongyan Shen, Guochao Wu

    Marine gravimeter has been proved to be the primary technique to efficiently obtain middle-to-short wavelength signals of the earth’s gravity field in geodesy, geodynamics and marine sciences research. In recent years, some prototypes of inertial platform and strapdown marine gravimeters have been developed, where the inertial platform gravimeter systems include CHZ-II and ZL11, and strapdown gravimeter

    更新日期:2020-07-02
  • Future Simulations of Tidal Disruption Events
    Space Sci. Rev. (IF 6.125) Pub Date : 2020-07-02
    Julian H. Krolik, Philip J. Armitage, Yanfei Jiang, Giuseppe Lodato

    Tidal disruption events involve numerous physical processes (fluid dynamics, magnetohydrodynamics, radiation transport, self-gravity, general relativistic dynamics) in highly nonlinear ways, and, because TDEs are transients by definition, frequently in non-equilibrium states. For these reasons, numerical solution of the relevant equations can be an essential tool for studying these events. In this

    更新日期:2020-07-02
  • Uncertainties in river discharge simulations of the upper Indus basin in the Western Himalayas
    J. Earth Syst. Sci. (IF 1.423) Pub Date : 2020-07-02
    P Priya, R Krishnan, Milind Mujumdar

    This study focuses on understanding and quantifying uncertainties in simulating river discharge in the Upper Indus Basin (UIB) of the Western Himalayas using a macro-scale semi-distributed hydrology model forced with multiple observed precipitation datasets and reanalysis products of near-surface wind-speed, maximum and minimum temperature during 2010–2012. We performed a suite of numerical simulations

    更新日期:2020-07-02
  • ASAS census of twins
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-07-01
    Volkan Bakış; Zeki Eker; Oğuzhan Sarı; Gökhan Yücel; Eda Sonbaş

    Twin binaries were identified among the eclipsing binaries with δ > –30° listed in the All Sky Automated Survey (ASAS) catalogue. In addition to the known twin binaries in the literature, 68 new systems have been identified and photometric and spectroscopic observations were done. Colour, spectral type, temperature, ratio of radii and masses of the components have been derived and are presented. Including

    更新日期:2020-07-01
  • Shapes and alignments of dark matter haloes and their brightest cluster galaxies in 39 strong lensing clusters
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-29
    Taizo Okabe; Masamune Oguri; Sébastien Peirani; Yasushi Suto; Yohan Dubois; Christophe Pichon; Tetsu Kitayama; Shin Sasaki; Takahiro Nishimichi

    We study shapes and alignments of 45 dark matter (DM) haloes and their brightest cluster galaxies (BCGs) using a sample of 39 massive clusters from Hubble Frontier Field (HFF), Cluster Lensing And Supernova survey with Hubble (CLASH), and Reionization Lensing Cluster Survey (RELICS). We measure shapes of the DM haloes by strong gravitational lensing, whereas BCG shapes are derived from their light

    更新日期:2020-07-01
  • A MeerKAT survey of nearby nova-like cataclysmic variables
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-22
    D M Hewitt; M L Pretorius; P A Woudt; E Tremou; J C A Miller-Jones; C Knigge; N Castro Segura; D R A Williams; R P Fender; R Armstrong; P Groot; I Heywood; A Horesh; A J van der Horst; E Koerding; V A McBride; K P Mooley; A Rowlinson; B Stappers; R A M J Wijers

    We present the results of MeerKAT radio observations of 11 nearby nova-like cataclysmic variables (CVs). We have detected radio emission from IM Eri, RW Sex, V3885 Sgr, and V603 Aql. While RW Sex, V3885 Sgr, and V603 Aql had been previously detected, this is the first reported radio detection of IM Eri. Our observations have doubled the sample of non-magnetic CVs with sensitive radio data. We observe

    更新日期:2020-07-01
  • Opacity modelling of heavy-metal hot subdwarfs: photoionization of Sr0, Y+, and Zr2 +
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-20
    L Fernández-Menchero; C S Jeffery; C A Ramsbottom; C P Ballance.

    Heavy-metal hot subdwarfs (sdB and sdO) represent a small group of stars with unusually high concentrations of trans-iron elements in their atmospheres, having abundances |${\sim } 10\, 000$| times solar. One example is LS IV-14 116, where a number of heavy-metal absorption lines of Sr ii, Y iii, and Zr iv have been observed in the optical band |$4000\!-\!5000\, {\mathring{\rm A}}$|⁠. We use a fully

    更新日期:2020-07-01
  • The dust and cold gas content of local star-forming galaxies
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-18
    P Popesso; A Concas; L Morselli; G Rodighiero; A Enia; S Quai

    We use dust masses (Mdust) derived from far-infrared data and molecular gas masses (Mmol) based on CO luminosity to calibrate proxies based on a combination of the galaxy Balmer decrement, disc inclination, and gas metallicity. We use such proxies to estimate Mdust and Mmol in the local SDSS sample of star-forming galaxies (SFGs). We study the distribution of Mdust and Mmol along and across the main

    更新日期:2020-07-01
  • Environments of dwarf galaxies with optical AGN characteristics
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-17
    Mikkel T Kristensen; Kevin Pimbblet; Samantha Penny

    This study aims to explore the relation between dwarf galaxies (M* ≤ 5 × 109 M⊙) with active galactic nuclei (AGNs) and their environment by comparing neighbourhood parameters of AGN and non-AGN samples. Using the NASA-Sloan Atlas, both the local environment and the immediate environment of dwarf galaxies with z ≤ 0.055 are analysed. Of the 145 155 galaxies in the catalogue, 62 258 of them are classified

    更新日期:2020-07-01
  • Fe iii emission in quasars: evidence for a dense turbulent medium
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-17
    Matthew J Temple; Gary J Ferland; Amy L Rankine; Paul C Hewett; N R Badnell; Connor P Ballance; Giulio Del Zanna; Roger P Dufresne

    Recent improvements to atomic energy-level data allow, for the first time, accurate predictions to be made for the Fe iii line emission strengths in the spectra of luminous, |$L_\text{bol}\simeq 10^{46}\!-\!10^{48}\mbox{${\rm \, erg}{\rm \, s}^{-1}\, $}$|⁠, active galactic nuclei. The Fe iii emitting gas must be primarily photoionized, consistent with observations of line reverberation. We use cloudy

    更新日期:2020-07-01
  • Helium abundances and its radial gradient from the spectra of H ii regions and ring nebulae of the Milky Way
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-17
    J E Méndez-Delgado; C Esteban; J García-Rojas; K Z Arellano-Córdova; M Valerdi

    We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 H ii regions and ring nebulae surrounding massive O-type stars. We revise the Galactocentric distances of the objects considering Gaia DR2 parallaxes (Gaia Collaboration 2018) and determine the physical conditions and the ionic abundance of He+ in a homogeneous way, using between 3 and 10 He i

    更新日期:2020-07-01
  • Radio constraints on dark matter annihilation in Canes Venatici I with LOFAR
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-13
    Martin Vollmann; Volker Heesen; Timothy W. Shimwell; Martin J Hardcastle; Marcus Brüggen; Günter Sigl; Huub J. A. Röttgering

    Dwarf galaxies are dark matter (DM) dominated and therefore promising targets for the search for weakly interacting massive particles (WIMPs), which are well-known candidates for DM. The annihilation of WIMPs produces ultrarelativistic cosmic ray electrons and positrons that emit synchrotron radiation in the presence of magnetic fields. For typical magnetic field strengths (few μG) and |$\mathcal {O}$|(GeV–TeV)

    更新日期:2020-07-01
  • A versatile tool for cluster lensing source reconstruction – I. Methodology and illustration on sources in the Hubble Frontier Field Cluster MACS J0717.5+3745
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-13
    Lilan Yang; Simon Birrer; Tommaso Treu

    We describe a general-purpose method to reconstruct the intrinsic properties of sources lensed by the gravitational potential of foreground clusters of galaxies. The tool lenstruction is implemented in the publicly available multipurpose gravitational lensing software lenstronomy, in order to provide an easy and fast solution to this common astrophysical problem. The tool is based on forward modelling

    更新日期:2020-07-01
  • The advection-dominated accretion flow for the anticorrelation between the X-ray photon index and the X-ray luminosity in neutron star low-mass X-ray binaries
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-12
    Erlin Qiao; B F Liu

    Observationally, an anticorrelation between the X-ray photon index Γ (obtained by fitting the X-ray spectrum between 0.5 and 10 keV with a single power law) and the X-ray luminosity L0.5-10 keV, i.e. a softening of the X-ray spectrum with decreasing L0.5-10 keV, is found in neutron star low-mass X-ray binaries (NS-LMXBs) in the range of |$L_{\rm 0.5\!-\!10\,keV}\sim 10^{34}\!-\!10^{36}\ \rm erg\ s^{-1}$|⁠

    更新日期:2020-07-01
  • Predicting the time variation of radio emission from MHD simulations of a flaring T-Tauri star
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-12
    C O G Waterfall; P K Browning; G A Fuller; M Gordovskyy; S Orlando; F Reale

    We model the time-dependent radio emission from a disc accretion event in a T-Tauri star using 3D, ideal magnetohydrodynamic simulations combined with a gyrosynchrotron emission and radiative transfer model. We predict for the first time, the multifrequency (1–1000 GHz) intensity and circular polarization from a flaring T-Tauri star. A flux tube, connecting the star with its circumstellar disc, is

    更新日期:2020-07-01
  • The fate of disc galaxies in IllustrisTNG clusters
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-12
    Gandhali D Joshi; Annalisa Pillepich; Dylan Nelson; Federico Marinacci; Volker Springel; Vicente Rodriguez-Gomez; Mark Vogelsberger; Lars Hernquist

    We study the stellar morphological evolution of disc galaxies within clusters in the TNG50 and TNG100 runs from the IllustrisTNG simulation suite. We select satellites of masses 109.7 ≤ M*, z = 0/M⊙ ≤ 1011.6 residing in clusters of masses 1014 ≲ M200c, z = 0/M⊙ ≤ 1014.6 at z = 0 and that were discs at accretion according to a kinematic morphology indicator (the circularity fraction). These are traced

    更新日期:2020-07-01
  • Activity of (6478) Gault during 2019 January 13–March 28
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-09
    Oleksandra Ivanova; Yuri Skorov; Igor Luk'yanyk; Dušan Tomko; Marek Husárik; Jürgen Blum; Oleg Egorov; Olga Voziakova

    We present the results of photometric observations of active asteroid (6478) Gault performed at heliocentric distances from 2.46 to 2.30 au and geocentric distances from 1.79 to 1.42 au between 2019 January 15 and March 28. Observations were carried out at the 2.5-m telescope of SAI MSU (Caucasian Mountain Observatory) on 2019 January 15 and at the 1.3 and 0.61-m telescopes (SPb) on 2019 February 6

    更新日期:2020-07-01
  • LOFAR observations of X-ray cavity systems
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-08
    L Bîrzan; D A Rafferty; M Brüggen; A Botteon; G Brunetti; V Cuciti; A C Edge; R Morganti; H J A Röttgering; T W Shimwell

    We present LOFAR observations at 120–168 MHz of 42 systems with possible X-ray cavities in their hot atmosphere, of which 17 are groups or ellipticals, 19 are nearby clusters (z < 0.3), and six are higher redshift clusters (z > 0.3). The X-ray cavities, formed by the radio lobes of the central active galactic nucleus (AGN), are evidence of radio-mode AGN feedback. In the groups and ellipticals sample

    更新日期:2020-07-01
  • A monitoring network for anomalous propagation of aeronautical VHF radio waves due to sporadic E in Japan
    Earth Planets Space (IF 2.075) Pub Date : 2020-07-01
    Keisuke Hosokawa, Jun Sakai, Ichiro Tomizawa, Susumu Saito, Takuya Tsugawa, Michi Nishioka, Mamoru Ishii

    We introduce a network observation of anomalous long-distance propagation of aeronautical navigation (NAV) very high-frequency (VHF) radio waves due to sporadic E layer (Es). The system has been operative since May 2019 at 6 stations in Japan. The receiver consists of a log-periodic antenna, air-band filter, software-defined radio and small computer which is capable of recording the strength of radio

    更新日期:2020-07-01
  • Setting the Stage: Planet Formation and Volatile Delivery
    Space Sci. Rev. (IF 6.125) Pub Date : 2020-07-01
    Julia Venturini, Maria Paula Ronco, Octavio Miguel Guilera

    The diversity in mass and composition of planetary atmospheres stems from the different building blocks present in protoplanetary discs and from the different physical and chemical processes that these experience during the planetary assembly and evolution. This review aims to summarise, in a nutshell, the key concepts and processes operating during planet formation, with a focus on the delivery of

    更新日期:2020-07-01
  • X-Ray Properties of TDEs
    Space Sci. Rev. (IF 6.125) Pub Date : 2020-07-01
    R. Saxton, S. Komossa, K. Auchettl, P. G. Jonker

    Observational astronomy of tidal disruption events (TDEs) began with the detection of X-ray flares from quiescent galaxies during the ROSAT all-sky survey of 1990–1991. The flares complied with theoretical expectations, having high peak luminosities (\(L_{\mathrm{x}}\) up to \(\ge 4\times 10^{44}~\text{erg/s}\)), a thermal spectrum with \(kT\sim \text{few} \times 10^{5}~\text{K}\), and a decline on

    更新日期:2020-07-01
  • Superrotation in Planetary Atmospheres
    Space Sci. Rev. (IF 6.125) Pub Date : 2020-07-01
    Takeshi Imamura, Jonathan Mitchell, Sebastien Lebonnois, Yohai Kaspi, Adam P. Showman, Oleg Korablev

    Superrotation is a dynamical regime where the atmosphere circulates around the planet in the direction of planetary rotation with excess angular momentum in the equatorial region. Superrotation is known to exist in the atmospheres of Venus, Titan, Jupiter, and Saturn in the solar system. Some of the exoplanets also exhibit superrotation. Our understanding of superrotation in a framework of circulation

    更新日期:2020-07-01
  • A thirty-four billion solar mass black hole in SMSS J2157–3602, the most luminous known quasar
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Christopher A Onken; Fuyan Bian; Xiaohui Fan; Feige Wang; Christian Wolf; Jinyi Yang

    From near-infrared spectroscopic measurements of the Mg ii emission line doublet, we estimate the black hole (BH) mass of the quasar, SMSS J215728.21–360215.1, as being (3.4 ± 0.6) × 1010 M⊙ and refine the redshift of the quasar to be z = 4.692. SMSS J2157 is the most luminous known quasar, with a 3000 Å luminosity of (4.7 ± 0.5) × 1047 erg s−1 and an estimated bolometric luminosity of 1.6 × 1048 erg s−1

    更新日期:2020-06-30
  • The possible disappearance of a massive star in the low-metallicity galaxy PHL 293B
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-30
    Andrew P Allan; Jose H Groh; Andrea Mehner; Nathan Smith; Ioana Boian; Eoin J Farrell; Jennifer E Andrews

    We investigate a suspected very massive star in one of the most metal-poor dwarf galaxies, PHL 293B. Excitingly, we find the sudden disappearance of the stellar signatures from our 2019 spectra, in particular the broad H lines with P Cygni profiles that have been associated with a massive luminous blue variable (LBV) star. Such features are absent from our spectra obtained in 2019 with the Echelle

    更新日期:2020-06-30
  • Perturbation Maps and the ring of Haumea
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-16
    Diogo M Sanchez; Rogerio Deienno; Antonio F B A Prado; Kathleen C Howell

    The dwarf planet Haumea is a trans-Neptunian object that is orbited by two moons and has a recently discovered ring. The particles of this ring are near the 3:1 resonance between the spin of Haumea and the orbital motion of the particles. In this work, the ring of Haumea is investigated using Perturbation Maps. These maps show the behaviour and impact of perturbations acting over particles around Haumea

    更新日期:2020-06-30
  • Three-dimensional models of core-collapse supernovae from low-mass progenitors with implications for Crab
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-15
    G Stockinger; H-T Janka; D Kresse; T Melson; T Ertl; M Gabler; A Gessner; A Wongwathanarat; A Tolstov; S-C Leung; K Nomoto; A Heger

    We present 3D full-sphere supernova simulations of non-rotating low-mass (∼9 M⊙) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions (∼0.5–1.0 × 1050 erg) of iron-core progenitors at the low-mass end of the core-collapse supernova

    更新日期:2020-06-30
  • Discovery and astrophysical properties of Galactic open clusters in dense stellar fields using Gaia DR2
    Mon. Not. R. Astron. Soc. (IF 5.356) Pub Date : 2020-06-15
    F A Ferreira; W J B Corradi; F F S Maia; M S Angelo; J F C Santos

    We report the discovery of 25 new open clusters resulting from a search in dense low Galactic latitude fields. We also provide, for the first time, structural and astrophysical parameters for the new findings and 34 other recently discovered open clusters using Gaia Data Release 2 (DR2) data. The candidates were confirmed by jointly inspecting the vector point diagrams and spatial distribution. The

    更新日期:2020-06-30
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