Gamma-Ray Bursts: 3. Short GRBs Brian Metzger, Columbia University - PowerPoint PPT Presentation

Gamma-Ray Bursts: 3. Short GRBs Brian Metzger, Columbia University

Binary Neutron Star Mergers Gravitational Waves Gravitational Waves Ω Ω G 3 M 2 " 1 dP dt = 48 NS NS NS NS a a c 5 a 4 P 5 10 Known Galactic NS-NS Binaries 10 Known Galactic NS-NS Binaries Hulse-Taylor Pulsar (Lorimer 2008) merge ~ 10 -5 " 10 -4 yr -1 T merge = 300 = 300 Myr Myr T merge ˙ N (Kalogera ( Kalogera et al. 2004) et al. 2004)

Gravitational Waves from Inspiral and Merger Credit: Kip Thorne Credit: Kip Thorne “chirp chirp” ” “ Ground-Based Virgo (Italy) Virgo (Italy) LIGO (North America) LIGO (North America) Interferometers LIGO 6th Science Run LIGO 6th Science Run (2010) Range ~ 20-50 Mpc Mpc (2010) Range ~ 20-50 “Advanced “ Advanced” ” LIGO+Virgo LIGO+Virgo (~2016) Range ~ 300-600 Mpc Mpc (~2016) Range ~ 300-600

Numerical Simulation - Two 1.4 M  NSs Numerical Simulation - Two 1.4 M  Courtesy M. Shibata (Tokyo U)

Numerical Simulation - Two 1.4 M  NSs Numerical Simulation - Two 1.4 M  Courtesy M. Shibata (Tokyo U)

Re Remn mnant Ac Accretion Di Disk (e.g. Ruffert & Janka 1999; Shibata & Taniguchi 2006; Faber et al. 2006; Chawla et al. 2010; Duez et al. 2010; Foucalt 2012; Deaton et al. 2013) Lee et al. 2004 • Disk Mass ~0.01 - 0.1 M  & Size ~ 10-100 km • Hot (T > MeV) & Dense ( ρ ~ 10 8 -10 12 g cm -3 ) • Neutrino Cooled: ( τ ν ~ 0.01-100) e " + p # $ e + n e + + n " # • Equilibrium ⇒ Y e ~ 0.1 vs. . e + p vs M ~ 10 " 2 " 10 M ! s -1 ˙ Accretion Rate Accretion Rate Short GRB 1/ 2 ( 3/ 2 H / R ) 1 ) 2 " % " % " % " % M • R d Engine? t visc ~ 0.1 s $ ' $ ' $ ' $ ' 3 M ! # 0.1 & # 100 km & # 0.5 & # &

Relativistic Jets and Short GRBs ν Powered Aloy et al. 2005 Rezzolla et al. 2010 MHD Powered Zhang & MacFadyen 2009

Shor Short & & Long Gamma-Ray Bursts BATSE Bursts Nakar 07 Nakar 07

Short & Shor & Long Gamma-Ray Bursts Long GRBs = Death of Massive Stars BATSE Bursts Star-Forming Host Galaxies (z avg ~2-3) Supernova Connection GRB 030329 ⇔ SN 2003dh Nakar 07 Nakar 07 Stanek et al. 2003

Short & Shor & Long Gamma-Ray Bursts Long GRBs = Death of Massive Stars BATSE Bursts Star-Forming Host Galaxies (z avg ~2-3) Supernova Connection GRB 030329 ⇔ SN 2003dh Nakar 07 Nakar 07 Stanek et al. 2003 Short ??? ???

Short GRB Host Galaxies GRB050724 Swift Swift Berger+05 z = 0.258 SFR < 0.03 M  yr -1 GRB050709 GRB050509b z = 0.16 SFR = 0.2 M  yr -1 Bloom+ 06 z = 0.225 HUBBLE Fox+05 KECK Bloom+06 SFR < 0.1 M  yr -1

Short GRB Host Galaxies GRB050724 Swift Swift Berger+05 • Lower redshift (z ~ 0.1-1) • E iso ~ 10 49-51 ergs GRB050724 z = 0.258 • Older Progenitor SFR < 0.03 M  yr -1 Population (e.g. Fong+ 2010; Leibler & Berger 2010) GRB050709 GRB050509b z = 0.16 SFR = 0.2 M  yr -1 Bloom +06 Bloom+ 06 No Supernova z = 0.225 HUBBLE Fox+05 KECK Bloom+06 SFR < 0.1 M  yr -1

Berger 2013

Radial Offsets from Host Galaxy Faucher-Giguere & Berger 2013 Kaspi 2006 In place pulsar velocity (km s -1 ) NS receive kick velocity v k ~ 100 km s -1 > v esc " % " % v t D = 100 kpc $ ' $ ' ⇒ short GRBs may occur outside host galaxy 100 km s -1 # & Gyr # &

Not that Short After All….  1/4 Swift Short Bursts have X-ray Tails GRB 050709  Rapid Variability ⇒ Ongoing Engine Activity  Energy up to ~30 times Burst Itself! Extended Emission Extended Emission GRB080503 S EE /S GRB ~ 30 Perley, BDM et al. 2009 BATSE Examples (Norris & Bonnell 2006)

Why Two Timescales? Why the Delay? ? t accretion ~ 0.1-1 s ??? Lee et al. (2004) Lee et al. (2004)

Viscous Evolution of the Viscous Evolution of the Remnant Disk Remnant Disk Local Disk Mass Σπ r 2 (M  ) Metzger, Piro & Quataert 2008, 2009 Angular Momentum Angular Momentum " t = 3 % ( " # " r r 1/ 2 " " ( ) " r $ # r 1/ 2 ' * r & ) 1/ 2 J = M d R d v K " M d R d BH $ 2 # R d " M d Entropy Entropy t = 0.01 s T dS dt = ˙ visc " ˙ q q # t = 1 s Heating Heating Cooling Cooling

Late-Time Disk Outflows ( Late-Time Disk Outflows (‘Evaporation vaporation’) After t ~ After t ~ 1 seconds, R ~ 300 km & 1 seconds, R ~ 300 km & T < 1 T < 1 MeV MeV • Recombination: n + p ⇒ He E BIND ~ GM BH m n /2R ~ 5 5 MeV MeV nucleon nucleon -1 -1 E BIND ~ GM BH m n /2R ~ E NUC ~ 7 7 MeV MeV nucleon nucleon -1 -1 Δ E NUC ~ Δ • Thick Disks Marginally Bound

Late-Time Disk Outflows ( Late-Time Disk Outflows (‘Evaporation vaporation’) After t ~ After t ~ 1 seconds, R ~ 300 km & 1 seconds, R ~ 300 km & T < 1 T < 1 MeV MeV • Recombination: n + p ⇒ He } E BIND ~ GM BH m n /2R ~ 5 5 MeV MeV nucleon nucleon -1 -1 E BIND ~ GM BH m n /2R ~ Disk Blows ⇒ E NUC ~ 7 7 MeV MeV nucleon nucleon -1 -1 Δ E NUC ~ Apart Δ • Thick Disks Marginally Bound BH Sizable Fraction of Initial Disk Unbound! Sizable Fraction of Initial Disk Unbound!

Axisymmetric Torus Evolution (Fernandez & Metzger 2012, 2013) • P-W potential with M BH = 3,10 M  • hydrodynamic α viscosity Equilibrium Torus M t ~ 0.01-0.1 M  R 0 ~ 50 km • NSE recombination 2n +2p ⇒ 4 He uniform Y e = 0.1 • run-time Δ t ~ 1000-3000 t orb • neutrino self-irradiation: “light bulb” + optical depth corrections: R ∈ [2,2000] R g angular emission pattern N r = 64 per decade peak emission N θ = 56 radius

Late Disk Outflows (Evaporation) ˙ M out (with " recombination) ˙ M ˙ M out (NO " recombination) BH • unbound outflow powered by viscous heating and α recombination • neutrino heating subdominant Time (s) outflow robust M ej ~ 0.05 M 0.05 M t t V ej ~ 0.1 c

Why Two Timescales? Why the Delay? ? t accretion ~ 0.1-1 s ??? Lee et al. (2004) Lee et al. (2004)

Stable Neutron Star Remnant? (e.g. Rasio 99; BDM+08; Ozel et al. 2010; Bucciantini et al. 2012; Zhang 13; Giacomazzo & Perna 13; Falcke & Rezzolla 13; Kiziltan 2013) • Requires: low total mass binary, stiff EOS*, and/or mass loss during merger *supported by recent discovery of 2M  NS by Demorest et al. 2011 • Rotating near centrifugal break-up with spin period P ~ 1 ms • Magnetic field amplified by rotational energy ⇒ “Magnetar” ? (e.g. Thompson & Duncan 92; Price & Rosswog 2006; Zrake & MacFadyen 2013) Giacomazzo & Perna 2013

Magnetar Spin-Down Powered Extended Emission (BDM et al. 2008; Bucciantini, BDM et al. 2012) Theoretical Light Curves Magnetar wind confined by merger ejecta vs. observed X-ray tails (magnetar outflow model from Metzger et al. 2011) Merger P 0 = 1.5 ms, Jet B dip = 2 × 10 15 G Ejecta Bucciantini et al. 2011 Magnetar Wind Jet may continue to inject energy into forward shock or produce lower level prompt emission (Zhang & Meszaros 2001; Dall’Osso et al. 2011; Rowlinson et al. 2013; Gompertz et al. 2013)

Radio constraints on long-lived NS merger remnants (BDM & Bower 2014) 1.4 GHz Luminosity (erg s -1 ) • Rotational energy eventually transferred to ISM ⇒ bright radio emission • Observed 7 short GRBs with VLA on timescales ~1-3 years after burst Rest-Frame Time Since GRB (years) • NO DETECTIONS ⇒ rules out stable NS remnant in 2 GRBs with Radio survey known high ISM densities constraints Frail et al. 2012 • Additional EVLA observations now would be much more constraining 10 -4 yr -1 gal -1 • Upcoming radio surveys (e.g. ASKAP) will strongly constrain population of stable NS merger remnants ⇒ indirectly probes EoS

Accretion-Induced Collapse (AIC) (e.g. Nomoto & Kondo 1991) • O-Ne WD built to M chandra • Collapse of rapidly-rotating WD ⇒ Disk around PNS: M disk ~ 10 -2 - 0.3 M  • Evolution similar to NS merger disks (Metzger+ 08,09) Nomoto & Kondo 1991

Similar Systems - Distinct Origins NS-NS / BH-NS / BH-NS NS-NS BH Mergers Mergers M ~ 0.01-0.1 M 0.01-0.1 M  M ~  R ~ 100 km Accretion- Accretion- Induced Induced NS Collapse Collapse Neutron Star Circinus X-1 Γ > 15 ! (Fender et al. 2004)

Theoretical Light Curves Magnetar wind confined by merger ejecta vs. observed X-ray tails (magnetar outflow model from Metzger et al. 2011) Merger P 0 = 1.5 ms, Jet B dip = 2 × 10 15 G Ejecta Bucciantini et al. 2011 Magnetar Wind

The Composition of Ultra High Energy Cosmic Rays Pierre Auger Observatory protons RMS(X max ) 〈 X max 〉 Iron Highest energy Energy (eV) UHECRs dominated by heavy nuclei ! PAO Collaboration (review by Kotera & Olinto 2011)

Candidate Astrophysical Sources Hillas: R L = E/ZeB < R source Magnetic Field Strength UHECR candidates Source Size

Candidate Astrophysical Sources Hillas: R L = E/ZeB < R source Z ~ ?? Magnetic Field Strength UHECR candidates Z < 10 Z � Z < Z � Source Size