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R-Process Elements from Magnetorotational Hypernovae
r-Process elements from magnetorotational hypernovae D. Yong1,2*, C. Kobayashi3,2, G. S. Da Costa1,2, M. S. Bessell1, A. Chiti4, A. Frebel4, K. Lind5, A. D. Mackey1,2, T. Nordlander1,2, M. Asplund6, A. R. Casey7,2, A. F. Marino8, S. J. Murphy9,1 & B. P. Schmidt1 1Research School of Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia 3Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, AL10 9AB, UK 4Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden 6Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany 7School of Physics and Astronomy, Monash University, VIC 3800, Australia 8Istituto NaZionale di Astrofisica - Osservatorio Astronomico di Arcetri, Largo Enrico Fermi, 5, 50125, Firenze, Italy 9School of Science, The University of New South Wales, Canberra, ACT 2600, Australia Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1–3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis4–6. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars7–13. -
Chapter 22 Neutron Stars and Black Holes Units of Chapter 22 22.1 Neutron Stars 22.2 Pulsars 22.3 Xxneutron-Star Binaries: X-Ray Bursters
Chapter 22 Neutron Stars and Black Holes Units of Chapter 22 22.1 Neutron Stars 22.2 Pulsars 22.3 XXNeutron-Star Binaries: X-ray bursters [Look at the slides and the pictures in your book, but I won’t test you on this in detail, and we may skip altogether in class.] 22.4 Gamma-Ray Bursts 22.5 Black Holes 22.6 XXEinstein’s Theories of Relativity Special Relativity 22.7 Space Travel Near Black Holes 22.8 Observational Evidence for Black Holes Tests of General Relativity Gravity Waves: A New Window on the Universe Neutron Stars and Pulsars (sec. 22.1, 2 in textbook) 22.1 Neutron Stars According to models for stellar explosions: After a carbon detonation supernova (white dwarf in binary), little or nothing remains of the original star. After a core collapse supernova, part of the core may survive. It is very dense—as dense as an atomic nucleus—and is called a neutron star. [Recall that during core collapse the iron core (ashes of previous fusion reactions) is disintegrated into protons and neutrons, the protons combine with the surrounding electrons to make more neutrons, so the core becomes pure neutron matter. Because of this, core collapse can be halted if the core’s mass is between 1.4 (the Chandrasekhar limit) and about 3-4 solar masses, by neutron degeneracy.] What do you get if the core mass is less than 1.4 solar masses? Greater than 3-4 solar masses? 22.1 Neutron Stars Neutron stars, although they have 1–3 solar masses, are so dense that they are very small. -
One Or Several Populations of Fast Radio Burst Sources?
One or several populations of fast radio burst sources? M. Caleb1, L. G. Spitler2 & B. W. Stappers1 1Jodrell Bank Centre for Astrophysics, the University of Manchester, Manchester, UK. 2Max-Planck-Institut fu¨r Radioastronomie, Bonn, Germany. arXiv:1811.00360v1 [astro-ph.HE] 1 Nov 2018 1 To date, one repeating and many apparently non-repeating fast radio bursts have been de- tected. This dichotomy has driven discussions about whether fast radio bursts stem from a single population of sources or two or more different populations. Here we present the arguments for and against. The field of fast radio bursts (FRBs) has increasingly gained momentum over the last decade. Overall, the FRBs discovered to date show a remarkable diversity of observed properties (see ref 1, http://frbcat.org and Fig. 1). Intrinsic properties that tell us something about the source itself, such as polarization and burst profile shape, as well as extrinsic properties that tell us something about the source’s environment, such as the magnitude of Faraday rotation and multi-path propagation effects, do not yet present a coherent picture. Perhaps the most striking difference is between FRB 121102, the sole repeating FRB2, and the more than 60 FRBs that have so far not been seen to repeat. The observed dichotomy suggests that we should consider the existence of multiple source populations, but it does not yet require it. Most FRBs to date have been discovered with single-pixel telescopes with relatively large angular resolutions. As a result, the non-repeating FRBs have typically been localized to no bet- ter than a few to tens of arcminutes on the sky (Fig. -
Searching for Gravitational Waves
Astronomy group seminar, University of Southampton, Jan 2015 LIGO-DCC G1500072 1. Gravitational wave (GW) background What are gravitational waves? • Gravitational waves are a direct prediction of Einstein’s General Theory of Relativity • Solutions to (weak field) Einstein equations in vacuum are wave equations 휕2 − + 훻2 ℎ휇휈 = −16휋푇휇휈 휕푡 2 Vacuum so stress- energy tensor 2 휕 푇휇휈 = 0 − + 훻2 ℎ휇휈 = 0 휕푡 2 휇휈 휇휈 휇 ℎ = 퐴 exp 푘휇 푥 • “Ripples in space-time” What are GWs? • Einstein first predicted GWs in 1916 paper • This had a major error – the waves carried no energy! Einstein, “Näherungsweise Integration der Feldgleichungen der Gravitation“, Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften, 1916 What are GWs? • Corrected in 1918 paper which introduced the now famous “quadrupole formula” Einstein, “Über Gravitationswellen“, Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften, 1918 What are GWs Source: Bulk Motion Oscillating Tidal Field Observer Detects Produces Changing Tidal Field Propagates (Unobstructed) Distortion Strain to Observer 푙 + Δ푙 푙 Δ푙 Strain: ℎ = 푙 2 퐺 mass quadruple Quadrupole ℎ(푡) = 퐼( 푡) formula: 푟 푐4 -45 source distance (1/r - ~ 8x10 small number! amplitude not power!) What are GWs? For two 1.4 M⊙ neutron stars 2 퐺 mass near coalescence at a distance of ℎ(푡) = 퐼( 푡) quadruple 10 Mpc ℎ~1.4 × 10−22 푟 푐4 -45 Displacement measured by 4km long ~ 8x10 detector ~5.6 × 10−19m - about 1/10000th source distance (1/r - amplitude not power!) diameter of a proton, or measuring change in distance to α Centauri to ~1/10th diameter of a human hair! • Detectable gravitational waves (GWs) will only come from the most massive and energetic systems in the universe e.g. -
Central Engines and Environment of Superluminous Supernovae
Central Engines and Environment of Superluminous Supernovae Blinnikov S.I.1;2;3 1 NIC Kurchatov Inst. ITEP, Moscow 2 SAI, MSU, Moscow 3 Kavli IPMU, Kashiwa with E.Sorokina, K.Nomoto, P. Baklanov, A.Tolstov, E.Kozyreva, M.Potashov, et al. Schloss Ringberg, 26 July 2017 First Superluminous Supernova (SLSN) is discovered in 2006 -21 1994I 1997ef 1998bw -21 -20 56 2002ap Co to 2003jd 56 2007bg -19 Fe 2007bi -20 -18 -19 -17 -16 -18 Absolute magnitude -15 -17 -14 -13 -16 0 50 100 150 200 250 300 350 -20 0 20 40 60 Epoch (days) Superluminous SN of type II Superluminous SN of type I SN2006gy used to be the most luminous SN in 2006, but not now. Now many SNe are discovered even more luminous. The number of Superluminous Supernovae (SLSNe) discovered is growing. The models explaining those events with the minimum energy budget involve multiple ejections of mass in presupernova stars. Mass loss and build-up of envelopes around massive stars are generic features of stellar evolution. Normally, those envelopes are rather diluted, and they do not change significantly the light produced in the majority of supernovae. 2 SLSNe are not equal to Hypernovae Hypernovae are not extremely luminous, but they have high kinetic energy of explosion. Afterglow of GRB130702A with bumps interpreted as a hypernova. Alina Volnova, et al. 2017. Multicolour modelling of SN 2013dx associated with GRB130702A. MNRAS 467, 3500. 3 Our models of LC with STELLA E ≈ 35 foe. First year light ∼ 0:03 foe while for SLSNe it is an order of magnitude larger. -
Modeling Hyperenergetic and Superluminous Supernovae
Modeling hyperenergetic and superluminous supernovae Philipp Mösta Einstein fellow @ UC Berkeley [email protected] Roland Haas, Goni Halevi, Christian Ott, Sherwood Richers, Luke Roberts, Erik Schnetter BlueWaters symposium 2017 May 17, 2017 Astrophysics of core-collapse supernovae M82/Chandra/NASA ~ Galaxy evolution/feedback Heavy element nucleosynthesis Birth sites of black holes / neutron stars 2 Neutrinos New era of transient science • Current (PTF, DeCAM, ASAS-SN) and upcoming wide-field time domain astronomy (ZTF, LSST, …) -> wealth of data • adv LIGO / gravitational waves detected • Computational tools at dawn of new exascale era Image: PTF/ZTF/COO Image: LSST 3 New era of transient science • Current (PTF, DeCAM, ASAS-SN) and upcoming wide-field time domain astronomy (ZTF, LSST, …) -> wealth of data • adv LIGO / gravitational waves detected • Computational tools at dawn of new exascale era Transformative years ahead for our understanding of these events Image: PTF/ZTF/COO Image: LSST 4 Hypernovae & GRBs • 11 long GRB – core-collapse supernova associations. • All GRB-SNe are stripped envelope, show outflows v~0.1c • But not all stripped-envelope supernovae come with GRBs • Trace low metallicity and low redshift Neutrino mechanism is inefficient; can’t deliver a hypernova 5 Superluminous supernovae Some events: stripped envelope no interaction 45 Elum ~ 10 erg 52 Erad up to 10 erg Gal-Yam+12 6 Superluminous / hyperenergetic supernovae SLSN Ic lGRBs SN Ic-bl Common engine? 7 Core collapse basics Iron core Protoneutron star r~30km -
Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae
SLAC-PUB-12126 astro-ph/0601111 September 2006 Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae Shigehiro Nagataki1,2, Akira Mizuta3, Katsuhiko Sato4,5 ABSTRACT Two-dimensional hydrodynamic simulations are performed to investigate ex- plosive nucleosynthesis in a collapsar using the model of MacFadyen and Woosley (1999). It is shown that 56Ni is not produced in the jet of the collapsar suffi- ciently to explain the observed amount of a hypernova when the duration of the explosion is ∼10 sec, which is considered to be the typical timescale of explosion in the collapsar model. Even though a considerable amount of 56Ni is synthesized if all explosion energy is deposited initially, the opening angles of the jets become too wide to realize highly relativistic outflows and gamma-ray bursts in such a case. From these results, it is concluded that the origin of 56Ni in hypernovae associated with GRBs is not the explosive nucleosynthesis in the jet. We consider that the idea that the origin is the explosive nucleosynthesis in the accretion disk is more promising. We also show that the explosion becomes bi-polar naturally due to the effect of the deformed progenitor. This fact suggests that the 56Ni synthesized in the accretion disk and conveyed as outflows are blown along to the rotation axis, which will explain the line features of SN 1998bw and double peaked line features of SN 2003jd. Some fraction of the gamma-ray lines from 56Ni decays in the jet will appear without losing their energies because the jet becomes optically thin before a considerable amount of 56Ni decays as long as the jet is a relativistic flow, which may be observed as relativistically Lorentz boosted line profiles in future. -
Observations of Crab Nebula and Pulsar with VERITAS
University of California Los Angeles Observations of Crab Nebula and Pulsar with VERITAS A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Physics by Ozlem¨ C¸elik 2008 c Copyright by Ozlem¨ C¸elik 2008 The dissertation of Ozlem¨ C¸elik is approved. Katsushi Arisaka Ferdinand Coroniti Kevin McKeegan Ren´eOng, Committee Chair University of California, Los Angeles 2008 ii To my parents . for their endless love and support at all times. iii Table of Contents 1 Gamma-Ray Astronomy ........................ 1 1.1 Introduction.............................. 1 1.2 GammaRays ............................. 2 1.3 MotivationsforGamma-RayAstronomy . 4 1.4 Gamma-RayDetectors ........................ 6 1.4.1 Space-BasedDetectors . 6 1.4.2 Ground-basedDetectors . 12 1.4.3 AlternativeDetectors. 16 1.5 Gamma-RaySources ......................... 16 1.5.1 GalacticSources ....................... 17 1.5.2 ExtragalacticSources. 21 1.6 GuidetoThesis............................ 24 2 Pulsars and Their Nebulae ...................... 25 2.1 Birth of the PWNe Complex: Supernovae . 26 2.2 ThePulsarStar............................ 29 2.2.1 ConnectiontoNeutronStars. 29 2.2.2 CharacteristicsofPulsars . 30 2.2.3 Non-Thermal Radiation Mechanisms at Work in PWNe . 33 2.2.4 PulsedEmission. .. .. 38 2.2.5 HE Pulsed Emission Models . 40 iv 2.2.6 Predictions of HE Emission Models . 44 2.2.7 VHE gamma-ray Observations of Pulsed Emission . 50 2.3 PulsarWindNebulae......................... 52 2.3.1 RegionsinaPWN ...................... 52 2.3.2 The Central Pulsar: The Energy Source . 53 2.3.3 Pulsar Winds: Energy Transport between Pulsar and Nebula 55 2.3.4 The Wind Termination Shock . 57 2.3.5 The Nebular Emission . -
Detection of a Type Iin Supernova in Optical Follow-Up Observations of Icecube Neutrino Events Magellan Workshop, 17–18 March 2016, DESY Hamburg
Detection of a Type IIn Supernova in Optical Follow-Up Observations of IceCube Neutrino Events Magellan Workshop, 17{18 March 2016, DESY Hamburg Markus Voge, Nora Linn Strotjohann, Alexander Stasik 17 March 2016 Target: transient sources (< 100 s • neutrino burst): GRBs (Waxman & Bahcall 1997, Murase • & Nagataki 2006) SNe with jets (Razzaque, Meszaros, • Waxman 2005) More exotic phenomena? E.g. Fast • Radio Bursts (FRBs)? (Falcke & Rezzolla 2013) Online Neutrino Analysis Automatic search for interesting IceCube neutrino events • Realtime alerts sent to follow-up instruments • Multi-messenger: Combination with other data fruitful • Follow-up ensures access to data • 2 / 15 Online Neutrino Analysis Automatic search for interesting IceCube neutrino events • Realtime alerts sent to follow-up instruments • Multi-messenger: Combination with other data fruitful • Follow-up ensures access to data • Target: transient sources (< 100 s • neutrino burst): GRBs (Waxman & Bahcall 1997, Murase • & Nagataki 2006) SNe with jets (Razzaque, Meszaros, • Waxman 2005) More exotic phenomena? E.g. Fast • Radio Bursts (FRBs)? (Falcke & Rezzolla 2013) 2 / 15 The OFU and XFU system SN/GRB PTF (optical) Swift (X-ray) Alerts Alerts Madison/Bonn Iridium IceCube arXiv: 1309.6979 (p.40) 3 / 15 Online analysis scheme neutrino purity At least 8 coincident Trigger Level 0:0001% hits 2000 Hz ∼ Basic muon event se- Level 1 35 Hz 0:01% lection (tracks only) ∼ Up-going tracks Level 2 2 Hz 0:1% ∼ Neutrino selection OFU Level 3 mHz 90% (BDT) ∼ Neutrino multiplet ( 2ν): ≥ Time -
The Discovery of Frbs
Credit: Swinburne in Fast Radio Burst detection detection Burst FastRadio in Strategic uses of single dishes (and GB) (and singledishes uses of Strategic DuncanLorimer, Dept. Physics and of Astronomy, WestVirginia University FRB lowdown • 21 published so far • Flux > 0.5 Jy @ 1.4 GHz • Pulse widths > few ms • Highly dispersed • Weakly scattered • One FRB so far repeats! • Few arcmin localization • One counterpart so far • ~few x 1000/day/sky Credit: Thornton et al. (2013) What might FRBs probe? • New/exciting physics • Cosmological NS census? • Non-stellar origin? • Fundamental tests? • The intergalactic medium • Electron content → missing baryons? • Magnetic field || to line of sight • Cosmology • Rulers • DM halos, DM/DE parameterization Single-pulse search pipeline DM Cordes & McLaughlin (2003) Credit: Spitler et al. (2014) 2014: FRB 121102 at Arecibo at FRB 121102 2014: Credit: Masui et al. (2015) 2015: FRB 110523 at GBT at FRB 110523 2015: • More “theories” than bursts! • Colliding compact objects (e.g. NS-NS) • Supernovae • Collapsing NS → BH (blitzar) • Black hole absorbing NSs • Giant pulses from pulsars/magnetars • Neutron star – asteroid belt interaction • More exotic (strange) star interactions • Galactic Flare Stars • Light sails from ET • Dark matter • Cosmic strings • White holes No! Maybe? No! → → → or maybesomethingor else? … … 2016: FRB 121102 repeats! 121102 FRB 2016: Credit: Spitler et al. and Scholz et al. (2016) 2017: FRB 121102 localized! Credit: NRAO Credit: Chatterjee et al. (2017) z = 0.19 (2.3 billion yr) We -
Search for Neutrino Emission from Fast Radio Bursts with Icecube
Search for Neutrino Emission from Fast Radio Bursts with IceCube Donglian Xu Samuel Fahey, Justin Vandenbroucke and Ali Kheirandish for the IceCube Collaboration TeV Particle Astrophysics (TeVPA) 2017 August 7 - 11, 2017 | Columbus, Ohio Fast Radio Bursts - Discovery in 2007 2 e2 Lorimer et al.,Science 318 (5851): 777-780 2 ∆tdelay = 3 DM w− 2⇡mec · · 24 2 =1.5 10− s DM w− ⇥ · · 3 DM = n dl = 375 1cm− pc e ± Z “very compact” SMC J0045−7042 (70) J0111−7131 (76) J0113−7220 (125) “extragalactic”? J0045−7319 (105) J0131−7310 (205) Figure 2: Frequency evolution and integrated pulse shape of!the radio burst.4 The.8 survey0.4 data, collected on 2001δ Augusttwidth 24, are=4 shown. here6 ms as a two-dimensio ( nal ‘waterfall)− plot’± of intensity as a function of radio frequency versus time. The dispersion1.4GHzis clearly seen as a quadratic sweep across the frequency band, with broadening towards lower frequencies. From a measurement of the pulse delay across the receiver band using standard pulsar timing techniques, we determine the DM to be 375 dtI1 cm−3!pc. The two150 white lines50Jy separated byms 15 ms @ that 1 bound.4 GHz the pulse show the expected behavior± for the' cold-plasma dispersion± law assuming a DM of 375 cm−3 pc. The horizontal line at 1.34 GHz is an artifact in the data caused by a malfunctioning frequency Z ∼ channel. This plot is for one of the offset beams in which the digitizers were not saturated. By splitting the data into four frequency sub-bands we have measured both the half-power Galactic DM: pulse width• andA fluxtotal density spectrumof ~ over23 the observingFRBs bandwidth. -
Neutron Star Collapse Times, Gamma-Ray Bursts and Fast Radio Bursts
MNRAS 441, 2433–2439 (2014) doi:10.1093/mnras/stu720 The birth of black holes: neutron star collapse times, gamma-ray bursts and fast radio bursts ‹ Vikram Ravi1,2 and Paul D. Lasky1 Downloaded from https://academic.oup.com/mnras/article-abstract/441/3/2433/1126394 by California Institute of Technology user on 24 June 2019 1School of Physics, University of Melbourne, Parkville, VIC 3010, Australia 2CSIRO Astronomy and Space Science, Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia Accepted 2014 April 8. Received 2014 April 7; in original form 2013 November 29 ABSTRACT Recent observations of short gamma-ray bursts (SGRBs) suggest that binary neutron star (NS) mergers can create highly magnetized, millisecond NSs. Sharp cut-offs in X-ray afterglow plateaus of some SGRBs hint at the gravitational collapse of these remnant NSs to black holes. The collapse of such ‘supramassive’ NSs also describes the blitzar model, a leading candidate for the progenitors of fast radio bursts (FRBs). The observation of an FRB associated with an SGRB would provide compelling evidence for the blitzar model and the binary NS merger scenario of SGRBs, and lead to interesting constraints on the NS equation of state. We predict the collapse times of supramassive NSs created in binary NS mergers, finding that such stars collapse ∼10–4.4 × 104 s (95 per cent confidence) after the merger. This directly impacts observations targeting NS remnants of binary NS mergers, providing the optimal window for high time resolution radio and X-ray follow-up of SGRBs and gravitational wave bursts.