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Kilonovae and Short Hard Bursts A.K.A: Electromagnetic Counterparts to Gravitational Waves
Kilonovae and short hard bursts a.k.a: electromagnetic counterparts to gravitational waves Igor Andreoni for the Multi-Messenger Astronomy working group ZTF Phase II: NSF reverse site visit November 19th 2020 Electromagnetic counterparts to gravitational waves Short hard GRB - Are neutron star mergers the dominant sites for heavy element nucleosynthesis? - What extreme Physics can we learn? Kilonova (optical/IR) - How can we use kilonovae for cosmology? - What is the rate of binary neutron Gravitational star and neutron star-black hole mergers? Waves Image credit: NASA November 19th 2020 Igor Andreoni Finding kilonovae is challenging! Kilonovae are rare, fast and faint transients compared to supernovae Faint Fast modified from Andreoni+2018, LSST White Paper November 19th 2020 Igor Andreoni Why do we need ZTF? During the second LIGO-Virgo observing run (O2), the binary neutron star merger GW170817 was localized to 32 deg2 GW170817 (a couple of ZTF pointings) During O3 (2019-2020), the median localization for neutron star mergers was 4,480 deg2! …and the sources were more distant November 19th 2020 Igor Andreoni Gravitational Wave follow-up during O3 We used ZTF to follow-up 15 GW triggers that included at least one neutron star Kilonova luminosity function Kasliwal et al., ApJ, in press Second binary NS merger follow-up Coughlin et al., ApJ Letters, Vol 885, Issue 1, article id. L19, 13 pp. Constraints on NS-BH merger Anand & Coughlin et al., Nature Astronomy, in press November 19th 2020 Igor Andreoni Short, hard gamma-ray bursts (GRBs) We used ZTF to follow-up 8 short GRBs found by the Fermi satellite Ahumada et al., in prep. -
Supernovae Sparked by Dark Matter in White Dwarfs
Supernovae Sparked By Dark Matter in White Dwarfs Javier F. Acevedog and Joseph Bramanteg;y gThe Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics, Engineering Physics, and Astronomy, Queen's University, Kingston, Ontario, K7L 2S8, Canada yPerimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5, Canada November 27, 2019 Abstract It was recently demonstrated that asymmetric dark matter can ignite supernovae by collecting and collapsing inside lone sub-Chandrasekhar mass white dwarfs, and that this may be the cause of Type Ia supernovae. A ball of asymmetric dark matter accumulated inside a white dwarf and collapsing under its own weight, sheds enough gravitational potential energy through scattering with nuclei, to spark the fusion reactions that precede a Type Ia supernova explosion. In this article we elaborate on this mechanism and use it to place new bounds on interactions between nucleons 6 16 and asymmetric dark matter for masses mX = 10 − 10 GeV. Interestingly, we find that for dark matter more massive than 1011 GeV, Type Ia supernova ignition can proceed through the Hawking evaporation of a small black hole formed by the collapsed dark matter. We also identify how a cold white dwarf's Coulomb crystal structure substantially suppresses dark matter-nuclear scattering at low momentum transfers, which is crucial for calculating the time it takes dark matter to form a black hole. Higgs and vector portal dark matter models that ignite Type Ia supernovae are explored. arXiv:1904.11993v3 [hep-ph] 26 Nov 2019 Contents 1 Introduction 2 2 Dark matter capture, thermalization and collapse in white dwarfs 4 2.1 Dark matter capture . -
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Arxiv:2101.12220V2 [Astro-Ph.HE]
Neutron Stars Harboring a Primordial Black Hole: Maximum Survival Time Thomas W. Baumgarte1 and Stuart L. Shapiro2, 3 1Department of Physics and Astronomy, Bowdoin College, Brunswick, Maine 04011 2Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 3Department of Astronomy and NCSA, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 We explore in general relativity the survival time of neutron stars that host an endoparasitic, possibly primordial, black hole at their center. Corresponding to the minimum steady-state Bondi accretion rate for adiabatic flow that we found earlier for stiff nuclear equations of state (EOSs), we derive analytically the maximum survival time after which the entire star will be consumed by the black hole. We also show that this maximum survival time depends only weakly on the stiffness for polytropic EOSs with Γ ≥ 5/3, so that this survival time assumes a nearly universal value that depends on the initial black hole mass alone. Establishing such a value is important for constraining −16 −10 the contribution of primordial black holes in the mass range 10 M⊙ . M . 10 M⊙ to the dark-matter content of the Universe. Primordial black holes (PBHs) that may have formed the spherical, steady-state, Bondi accretion formula, in the early Universe (see, e.g., [1, 2]) have long been con- M 2ρ sidered candidates for contributing to, if not accounting M˙ =4πλ 0 (1) for, the mysterious and elusive dark matter (see, e.g., [3], a3 as well as [4] for a recent review). Constraints on the PBH contribution to the dark matter have been estab- for adiabatic flow ([18]; see also [19] for a textbook treat- lished by a number of different observations. -
Lecture Notes in Astrophysical Fluid Dynamics
Lecture Notes in Astrophysical Fluid Dynamics Mattia Sormani November 19, 2017 1 Contents 1 Hydrodynamics6 1.1 Introductory remarks..........................6 1.2 The state of a fluid...........................6 1.3 The continuity equation........................7 1.4 The Euler equation, or F = ma ....................8 1.5 The choice of the equation of state.................. 10 1.6 Manipulating the fluid equations................... 14 1.6.1 Writing the equations in different coordinate systems.... 14 1.6.2 Indecent indices......................... 16 1.6.3 Tables of unit vectors and their derivatives.......... 17 1.7 Conservation of energy......................... 18 1.8 Conservation of momentum...................... 21 1.9 Lagrangian vs Eulerian view...................... 21 1.10 Vorticity................................. 22 1.10.1 The vorticity equation..................... 23 1.10.2 Kelvin circulation theorem................... 24 1.11 Steady flow: the Bernoulli's equation................. 26 1.12 Rotating frames............................. 27 1.13 Viscosity and thermal conduction................... 28 1.14 The Reynolds number......................... 33 1.15 Adding radiative heating and cooling................. 35 1.16 Summary................................ 36 1.17 Problems................................. 37 2 Magnetohydrodynamics 38 2.1 Basic equations............................. 38 2.2 Magnetic tension............................ 44 2.3 Magnetic flux freezing......................... 45 2.4 Magnetic field amplification..................... -
Numerical Hydrodynamics in General Relativity
Numerical hydrodynamics in general relativity Jos´eA. Font Departamento de Astronom´ıay Astrof´ısica Edificio de Investigaci´on “Jeroni Mu˜noz” Universidad de Valencia Dr. Moliner 50 E-46100 Burjassot (Valencia), Spain Abstract The current status of numerical solutions for the equations of ideal general rel- ativistic hydrodynamics is reviewed. With respect to an earlier version of the article the present update provides additional information on numerical schemes and extends the discussion of astrophysical simulations in general relativistic hy- drodynamics. Different formulations of the equations are presented, with special mention of conservative and hyperbolic formulations well-adapted to advanced numerical methods. A large sample of available numerical schemes is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. A comprehensive summary of astrophysical simulations in strong gravitational fields is presented. These include gravitational collapse, accretion onto black holes and hydrodynamical evolutions of neutron stars. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances on the formulation of the gravitational field and arXiv:gr-qc/0003101v2 12 May 2003 hydrodynamic equations and the numerical methodology designed to solve them. 1 Introduction The description -
Bondi-Hoyle Accretion
A Review of Bondi–Hoyle–Lyttleton Accretion Richard Edgar a aStockholms observatorium, AlbaNova universitetscentrum, SE-106 91, Stockholm, Sweden Abstract If a point mass moves through a uniform gas cloud, at what rate does it accrete ma- terial? This is the question studied by Bondi, Hoyle and Lyttleton. This paper draws together the work performed in this area since the problem was first studied. Time has shown that, despite the simplifications made, Bondi, Hoyle and Lyttleton made quite accurate predictions for the accretion rate. Bondi–Hoyle–Lyttleton accretion has found application in many fields of astronomy, and these are also discussed. Key words: accretion PACS: 95.30.Lz, 97.10.Gz, 98.35.Mp, 98.62.Mw 1 Introduction arXiv:astro-ph/0406166v2 21 Jun 2004 In its purest form, Bondi–Hoyle–Lyttleton accretion concerns the supersonic motion of a point mass through a gas cloud. The cloud is assumed to be free of self-gravity, and to be uniform at infinity. Gravity focuses material behind the point mass, which can then accrete some of the gas. This problem has found applications in many areas of astronomy, and this paper is an attempt to address the lack of a general review of the subject. I start with a short summary of the original work of Bondi, Hoyle and Lyt- tleton, followed by a discussion of the numerical simulations performed. Some issues in Bondi–Hoyle–Lyttleton accretion are discussed, before a brief sum- mary of the fields in which the geometry has proved useful. Email address: [email protected] (Richard Edgar). -
GW170817-Like Disk Produces a Blue Kilonova J
GW170817-Like Disk Produces a Blue Kilonova J. M. Miller, with: B. R. Ryan, J. C. Dolence, A. Burrows, C. L. Fryer, O. Korobkin, J. Lippuner, M. R. Mumpower, R. T. Wollaeger A Groundbreaking Discovery The Case For the Disk Nucleosynthesis Heat, neutrinos, and magnetic fields can drive a wind off On August 17, 2017, the in-spiral and I I We find structured outflow. I the disk. merger of two neutron stars was observed. I Polar material has high Ye and produces less-robust r-process. This wind may produce a less-robust r-process and be a This event is called GW170817. I I Midplane material has low Ye and produces more-robust r-process. source for the blue kilonova. I Events like this one drive short gamma ray I Structure persists in time! bursts, some of the most energetic events in I Depends on electron fraction Ye. Low Ye means robust the universe. r-process and implies a red kilonova. High means less robust r-process and implies a blue kilonova. I Mergers are sites of r-process Literature is sparse and divided on wind and r-process nucleosynthesis, where the heaviest elements Above: A spectrogram showing the I [3, 4, 5]. in our universe are formed. characteristic gravitational wave chirp due to Above: Volume rendering of a Result depends sensitively on complex interplay of I Many more events to come! GW170817. Image from [1]. I simulated accretion disk formed by a neutrino transport, general relativity, magnetic fields, and BNS merger. fluid dynamics. An In-Spiral Story Above: Left: Total mass in the outflow as a 4 4 Presenting νbhlight function of time. -
Accretion Processes on a Black Hole Sandip K
Contents Abstract ........................................... ............. 4 1: Introduction ..................................... .............. 5 1.1 Some General Issues Related to Black Hole Astrophysics . .................. 7 1.1.1 Formation of Black Holes ......................... ....................... 7 1.1.2 Fueling Active Galactic Nuclei . ........................ 9 1.1.3 Evolution of Galactic Centers .................... ....................... 12 1.1.4 Black Holes in Galactic Halos? .................... ..................... 13 1.1.5 Some Signatures of Black Holes .................... ..................... 14 1.2 Difference between Motions around a Newtonian Star and a BlackHole ... 16 1.3 Basics of Pseudo-Newtonian Geometries . .................... 21 1.4 Remarks About Units and Dimensions . .................. 23 2: Spherical Accretion ............................... ............ 24 2.1 Bondi Accretion on a Newtonian Star .................. ................... 25 2.1.1 Basic Equations ................................ ........................ 25 2.1.2 Phase Space Behaviour of the Bondi Flow . ................. 28 2.2 Bondi Flow on a Black Hole ........................... ................... 30 2.2.1 In Schwarzschild Geometry ....................... ....................... 30 2.2.2 In pseudo-Newtonian Geometry .................... ..................... 31 2.3 Bondi Flow with Simple Radiative Transfer . ................... 32 2.4 Bondi Flow with General Radiative Transfer . ................... 32 2.4.1 Single Temperature Solutions -
Optical Emission from a Kilonova Following a Gravitational-Wave-Detected Neutron-Star Merger
Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger Iair Arcavi1,2, Griffin Hosseinzadeh1,2, D. Andrew Howell1,2, Curtis McCully1,2, Dovi Poznanski3, Daniel Kasen4,5, Jennifer Barnes6, Michael Zaltzman3, 1,2 3 7 Sergiy Vasylyev , Dan Maoz and Stefano Valenti 1Department of Physics, University of California, Santa Barbara, CA 93106-9530, USA 2Las Cumbres Observatory, 6740 Cortona Dr Ste 102, Goleta, CA 93117-5575, USA 3School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel 4Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720- 8169, USA 5Departments of Physics and Astronomy, University of California, Berkeley, CA 94720- 7300, USA 6Columbia Astrophysics Laboratory, Columbia University, New York, NY, 10027, USA 7Department of Physics, University of California, 1 Shields Ave, Davis, CA 95616-5270, USA The merger of two neutron stars has been predicted to produce an optical- infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of neutron-rich species synthesized in the merger1-5. Evidence that short γ-ray bursts also arise from neutron star mergers has been accumulating6-8. In models2,9 of such mergers a small amount of mass (10−4-10−2 solar masses) with a low electron fraction is ejected at high velocities (0.1-0.3 times light speed) and/or carried out by winds from an accretion disk formed around the newly merged object10,11. This mass is expected to undergo rapid neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient1-3,9-14. -
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Arxiv:2009.12255V2 [Astro-Ph.HE] 9 Jan 2021
Mergers of binary neutron star systems: a multi-messenger revolution Elena Pian1,∗ 1INAF, Astrophysics and Space Science Observatory Correspondence*: Via Piero Gobetti 101, 40129 Bologna, Italy [email protected] ABSTRACT On 17 August 2017, less than two years after the direct detection of gravitational radiation from the merger of two ∼30 M⊙ black holes, a binary neutron star merger was identified as the source of a gravitational wave signal of ∼100 s duration that occurred at less than 50 Mpc from Earth. A short GRB was independently identified in the same sky area by the Fermi and INTEGRAL satellites for high energy astrophysics, which turned out to be associated with the gravitational event. Prompt follow-up observations at all wavelengths led first to the detection of an optical and infrared source located in the spheroidal galaxy NGC4993 and, with a delay of ∼10 days, to the detection of radio and X-ray signals. This paper revisits these observations and focusses on the early optical/infrared source, which was thermal in nature and powered by the radioactive decay of the unstable isotopes of elements synthesized via rapid neutron capture during the merger and in the phases immediately following it. The far-reaching consequences of this event for cosmic nucleosynthesis and for the history of heavy elements formation in the Universe are also illustrated. Keywords: neutron star, gravitational waves, gamma-ray burst, nucleosynthesis, r-process, kilonova 1 INTRODUCTION Although the birth of ”multi-messenger” astronomy dates back to the detection of the first solar neutrinos in the ’60s and was rejuvenated by the report of MeV neutrinos from SN1987A in the Large Magellanic Cloud, the detection of gravitational radiation from the binary neutron star merger on 17 August 2017 (GW170817A) marks the transition to maturity of this approach to observational astrophysics, as it is expected to open an effective window into the study of astrophysical sources that is not limited to exceptionally close (the Sun) or rare (Galactic supernova) events. -
Using Machine Learning for Transient Classification in Searches For
Draft version June 15, 2020 Typeset using LATEX twocolumn style in AASTeX62 Using machine learning for transient classification in searches for gravitational-wave counterparts Cosmin Stachie,1 Michael W. Coughlin,2, 3 Nelson Christensen,1 and Daniel Muthukrishna4 1Artemis, Universit´eC^oted'Azur, Observatoire C^oted'Azur, CNRS, CS 34229, F-06304 Nice Cedex 4, France 2Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 3School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA 4Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK ABSTRACT The large sky localization regions offered by the gravitational-wave interferometers require efficient follow-up of the many counterpart candidates identified by the wide field-of-view telescopes. Given the restricted telescope time, the creation of prioritized lists of the many identified candidates becomes mandatory. Towards this end, we use astrorapid, a multi-band photometric lightcurve classifier, to differentiate between kilonovae, supernovae, and other possible transients. We demonstrate our method on the photometric observations of real events. In addtion, the classification performance is tested on simulated lightcurves, both ideally and realistically sampled. We show that after only a few days of observations of an astronomical object, it is possible to rule out candidates as supernovae and other known transients. Keywords: gravitational waves 1. INTRODUCTION electromagnetic signatures -
Overview: Kilonova 1
Overview: Kilonova 1. Basics 2. Prospects for EM observa-ons 3. Signatures of r-process nucleosynthesis Masaomi Tanaka (Na-onal Astronomical Observatory of Japan) References (Reviews) • RosswoG, S. 2015 “The mul*-messenger picture of compact binary mergers” Interna*onal Journal of Modern Physics D, 24, 1530012-52 • Fernandez, R. & MetzGer, B. D. 2016 “Electromagne*c Signatures of Neutron Star Mergers in the Advanced LIGO Era” Annual Review of Nuclear and Par*cle Science, 66, 23 • Tanaka, M. 2016 “Kilonova/Macronova Emission from Compact Binary Mergers” Advances in Astronomy, 634197 • MetzGer, B. D. 2017 “Kilonovae” Living Reviews in Rela*vity, 20, 3 Timeline r-process Radioac-ve decay MerGer nucleosynthesis => kilonova Dynamical Wind < 10 ms ~< 100 ms < 1 sec ~ days energy deposi-on Diffusing out Masaru’s talk Francois’s talk My talk (Thursday) (Monday) (today) ν-driven winds from NS merger remnants 3145 5 Downloaded from http://mnras.oxfordjournals.org/ MerGer => see Masaru’s talkFigure 12. Vertical slices of the 3D domain (corresponding to the y 0 plane), recorded 20 ms after the beginning of the simulation. In the left-hand panel, 3 = we represent the logarithm of the matter density (in g cm− , left-hand side) and the projected fluid velocity (in units of c,ontheright-handside);thearrows indicate the direction of the projected velocity in the plane. On the right-hand panel, we represent the electron fraction (left-hand side) and the matter entropy 1 Dynamical ejecta (~< 10 ms)(in unit of kB baryon− ,right-handside). Post-dynamical ejecta (~< 100 ms) Side view at National Astronomical Observatory of Japan on January 1, 2016 Side view Top view Sekiguchi+16 Perego+14 Figure 13.