The Central Engines of Short Duration Gamma-Ray Bursts

Transcription

1 The Central Engines of Short Duration Gamma-Ray Bursts NS NS NS BH Brian Metzger Columbia University In Collaboration with Edo Berger, Wen-Fai Fong (Harvard), Tony Piro, Dan Perley (Caltech) Almudena Arcones, Gabriel Martinez-Pinedo (Darmstadt), Todd Thompson (OSU) Rodrigo Fernandez, Eliot Quataert, Dan Kasen, Geoff Bower (UC Berkeley) Indrek Vurm, Romain Hascoet, Andrei Beloborodov (Columbia), N. Bucciantini (INAF) Gamma-Ray Bursts November 14, YITP, Kyoto, Japan

2 Neutron Star Binary Mergers Advanced LIGO/Virgo (>2016) Range ~ Mpc Detection Rate ~ yr -1 NS Ω NS BH NS LIGO (North America) Sky Error Regions ~ deg 2 ~ galaxies Nissanke et a Virgo (Europe)

3 Astrophysical Origin of R-Process Nuclei Core Collapse Supernovae or NS Binary Mergers? Galactic r-process rate: M A >130 ~ 5 "10 #7 M! yr -1 (Qian et al. 2000) Requires (e.g. Hoffman et al. 1997) (1) low Y e (2) high entropy (3) fast expansion # N from NS Mergers: f R ~ merge &# % $ 10 "4 yr -1 ( M & ej % ' $ 10 "2 M (! ' Fraction of r-process from NS Mergers:

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

5 Electromagnetic Counterparts of NS-NS/NS-BH Mergers Afterglow Short GRB Kilonova Metzger & Berger 2012

6 Electromagnetic Counterparts of NS-NS/NS-BH Mergers Afterglow Short GRB Kilonova Metzger & Berger 2012

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

8 Remnant Accretion 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 Disk Mass ~ M & Size ~ km Hot (T > MeV) & Dense (ρ ~ g cm -3 ) Neutrino Cooled: (τ ν ~ ) Equilibrium e + + n " # e + p vs. Y e ~ 0.1 Accretion Rate " M t visc ~ 0.1 % $ ' # 3M! & 1/ 2 M ~ 10 "2 "10M! s -1 " ( % $ ' # 0.1& )1 3 / " R d % 2 " H /R% $ ' $ ' # 100 km& # 0.5 & e " + p # $ e + n )2 s Short GRB Engine?

9 Relativistic Jets and Short GRBs MHD Powered ν Powered Rezzolla et al OR Aloy et al. 2005

10 Relativistic Jets and Short GRBs Rezzolla et al MHD Powered How is [Large Scale] B-Field Generated? OR ν Powered Inefficient! (X-ray flares?) Aloy et al. 2005

11 Short GRBs Rare within aligo/virgo Volume θ j Detection Rate >z (yr -1 )!!! Swift Short GRBs Metzger & Berger 2012 Redshift z Detectable fraction by all sky γ-ray telescope f " ~ 3.4 # $ 2 j 2 ~ 0.07 % $ ( j ' * & 0.2) 2

12 Relativistic Blastwave Zhang & MacFadyen 2009

13 Electromagnetic Counterparts of NS-NS/NS-BH Mergers Afterglow Short GRB Kilonova Metzger & Berger 2012

14 Neutron-Rich Ejecta Dynamical Tidal Tails (e.g. Janka et al. 1999; Lee & Kluzniak 1999; Ruffert & Janka 2001; Rosswog et al. 2004; Rosswog 2005; Shibata & Taniguchi 2006; Giacomazzo et al. 2009; Duez et al. 2010; East et al. 2012; Hotokezaka et al. 2013; Bauswein+13) Full GR / Simple EOS / Circular M ej ~ M Y e " n p n p + n n # 0.05 Model M ej (10-3 M ) Hotokezaka et al Newtonian / Realistic EOS / Eccentric

15 Neutron-Rich Ejecta Dynamical Tidal Tails (e.g. Janka et al. 1999; Lee & Kluzniak 1999; Ruffert & Janka 2001; Rosswog et al. 2004; Rosswog 2005; Shibata & Taniguchi 2006; Giacomazzo et al. 2009; Duez et al. 2010; East et al. 2012; Hotokezaka et al. 2013; Bauswein+13) Full GR / Simple EOS / Circular M ej ~ M Y e " n p n p + n n # 0.05 Model M ej (10-3 M ) Hotokezaka et al Newtonian / Realistic EOS / Eccentric Disk Outflows Neutrino-Powered (Early) (e.g. McLaughlin & Surman 05; Surman+08; BDM+08; Dessart+09; Wanajo & Janka 12) Recombination-Powered (Late) (e.g. Beloborodov 08; BDM+08, 09; Lee+09; Fernandez & BDM 13) Y e ~??? M ej = f w M d ~ (f w /0.1) M

16 as used in Metzger et al (movie courtesy A. Arcones & G. Martinez-Pinedo) R-Process Network (neutron captures, photo-dissociations, α- and β-decays, fission)

17 Radioactive Heating of Merger Ejecta (BDM et al. 2010; Roberts et al. 2011; Goriely et al. 2011; Korobkin et al. 2012; Bauswein et al. 2013) Y e = 0.1 t -1.3 BDM et al Dominant β-decays at t ~ 1 day: 132,134,135 I, 128,129 Sb, 129 Te, 135 Xe Relatively insensitive to details (Y e, expansion history, NSE or not)

18 Bolometric Luminosity kilo-nova Color Evolution Fe Opacity Blackbody Model BDM et al. 2010

19 High Opacity of the Lanthanides (Kasen et al. 2013; Tanaka & Hotokezaka 2013) lanthanides Kasen et al Fe Tanaka & Hotokezaka 2013

20 Bolometric Luminosity kilo-nova Color Evolution Fe Opacity Blackbody Model BDM et al. 2010

21 Bolometric Luminosity kilo-nova Color Evolution Fe Opacity Blackbody Model BDM et al Y e > 0.3 Y e < 0.3

22 Neutron-Rich Ejecta Dynamical Tidal Tails (e.g. Janka et al. 1999; Lee & Kluzniak 1999; Ruffert & Janka 2001; Rosswog et al. 2004; Rosswog 2005; Shibata & Taniguchi 2006; Giacomazzo et al. 2009; Duez et al. 2010; East et al. 2012; Hotokezaka et al. 2013) Full GR / Simple EOS / Circular M ej ~ M Y e " 0.05 Model M ej (10-3 M ) Hotokezaka et al Newtonian / Realistic EOS / Eccentric Disk Outflows Neutrino-Powered (Early) (e.g. McLaughlin & Surman 05; Surman+08; BDM+08; Dessart+09) Recombination-Powered (Late) (e.g. Beloborodov 08; BDM+08, 09; Lee+09; Fernandez & BDM 13) Y e ~??? M ej = f w M d ~ (f w /0.1) M

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

24 Two Component Blue Light Curve Red Barnes & Kasen 2013 See also Grossman+13 or disk winds: r-process or Fe? tidal tail: r-process

25 Viscous Evolution of the Remnant Disk Metzger, Piro & Quataert 2008, 2009 Angular Momentum "# "t = 3 r " % "r r1/ 2 " & ' ( ) "r $#r1/ 2 ( ) * Local Disk Mass Σπr 2 (M ) dy e dt Heating Entropy T ds dt = q visc " q # Cooling Nuclear Composition BH = (" + " ), 1%Y % & 1% X )/ f e. + n # p$ e % p # n$ e ( ' 2 * 0 t = 0.01 s t = 1 s

26 Delayed Disk Winds ( Evaporation ) After t ~ 1 seconds, R ~ 300 km & T < 1 MeV Recombination: n + p He E BIND BIND ~ GM BH m n /2R ~ 5 MeV nucleon -1 ΔE NUC ~ 7 MeV nucleon -1 Thick Disks Marginally Bound

27 Delayed Disk Winds ( Evaporation ) After t ~ 1 seconds, R ~ 300 km & T < 1 MeV Recombination: n + p He E BIND BIND ~ GM BH m n /2R ~ 5 MeV nucleon -1 ΔE NUC ~ 7 MeV nucleon -1 Thick Disks Marginally Bound } Disk Blows Apart BH Sizable Fraction of Initial Disk Unbound!

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

29

30 Late Disk Outflows (Evaporation) M BH M out (with " recombination) M out (NO " recombination) unbound outflow powered by α recombination and viscous heating Time (s) neutrino heating subdominant

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

32 Y e Freeze Out t = 0.3 s t = 3 s t = 0.03 s Outflow Composition Mass per bin (M ) Y e entropy seed nuclei form (T< K) f X He # S & ~ 10 "2 % ( $ k b nuc -1 ' "3 / 2 # & ( $ 0.1 s' ( 1" 2Y e ) "1/ 2 t exp % then α-process (Woosley & Hoffman 92) n >100 " A >130 seed r-process (including lanthanides) r-process t exp X He

33 Composition (Preliminary)

34 Implications of Neutron-Rich Outflows Robust heavy r-process source (distinct from dynamical ejecta) M Galactic A>130 ~ 5 "10 #7 M! yr -1 (Qian 2000) Disk outflow emission hard to distinguish from tidal tail High opacity of lanthanides both produce RED and long (~WEEK) kilonova Grossman et al tidal tail disk wind Barnes & Kasen 2013

35 (cf. Berger+13; de Ugarte Postigo+13 ; Fong+13 ) 0.1 M 0.01 M If true, confirms association of short GRBs and NS-NS mergers

36 (see also Berger+13; de Ugarte Postigo+13; Fong+13 ) 0.1 M Implications (if true) confirms association of short GRBs with NS mergers counterpart would ~21-22 mag at 200 Mpc (detectable with big glass) minimum r-process contribution from NS mergers M r ~ R SGRB " M ej n gal 0.01 M ~ 10#8 Mpc -3 yr -1 " 0.03M! 0.03 gal Mpc -3 ~ 10 #8 M! yr -1 gal -1 ~ 0.02 M MW

37 Two Component Blue Light Curve Red Barnes & Kasen 2013 Grossman+13 or disk winds: r-process or Fe? tidal tail: r-process

38 Two Component Blue Light Curve Red Barnes & Kasen 2013 Grossman+13 disk winds: r-process or Fe? tidal tail: r-process

39 Two Component Blue Light Curve Red Barnes & Kasen 2013 Grossman+13 or disk winds: r-process or Fe? tidal tail: r-process

40 Two Component Blue Light Curve Red tidal tail: r-process disk winds: r-process or Fe? ν ν NS ν ν " e + n #e $ + p Barnes & Kasen 2013 Grossman+13

41 Neutrinos from NS Remnant Neutrino Luminosity (erg s -1 ) Prompt BH (Fernandez & BDM 13) Cooling NS Time after merger (s) 0.4 Y e 0.3 Disk outflow composition See talk by Albino Perego 0.2 ~ms ~100 ms NS Lifetime

42 Indefinitely Stable Neutron Star Remnant? (e.g. 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 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

43 Short GRBs with Extended Emission 1/5 Swift Short Bursts have X-ray Tails GRB Rapid Variability Ongoing Engine Activity Energy up to ~30 times Burst Itself! Extended Emission GRB S EE /S GRB ~ 30 Perley, BDM et al BATSE Examples (Norris & Bonnell 2006)

44 Magnetar Spin-Down Powered Extended Emission (BDM et al. 2008; Bucciantini, BDM et al. 2012; cf. Gao & Fan 2006 ) Magnetar wind confined by merger ejecta Theoretical Light Curves vs. observed X-ray tails (magnetar outflow model from Metzger et al. 2011) Bucciantini et al Jet Magnetar Wind Merger Ejecta P 0 = 1.5 ms, B dip = G 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)

45 time for jet to escape envelope jet power pulsar luminosity Millisecond Magnetar Wind Nebula Metzger & Piro, submitted (see also Yu et al. 2013) L j ~ L sd = µ2 " 4 c 3 Bromberg et al Jet choked behind ejecta at late times

46 time for jet to escape envelope jet power pulsar luminosity Millisecond Magnetar Wind Nebula Metzger & Piro, submitted (see also Yu et al. 2013) L j ~ L sd = µ2 " 4 c 3 Bromberg et al Jet choked behind ejecta at late times 1. 2.

47 Evolution Model for Millisecond Pulsar Wind Nebulae (BDM, Vurm, Hascoet & Beloborodov 2013; BDM & Piro 2013) Non-Thermal (UV / X-rays) Source: cooling e +/- pairs (pulsar) Sinks: PdV work, absorption by ejecta walls Thermal Bath (Optical) Source: re-emission of X-rays by ejecta walls Fe2+ Fe3+ Fe1+ Sinks: PdV work, radiative diffusion Ejecta Ionization State - Balance photo-ionization with recombination in ionized layer(s) - Sets ejecta albedo (thermalization efficiency)

48 Example (M ej =10-2 M ; B d =10 15 G) Optical [Solid], X-ray [Dashed] Light Curves

49 Example (M ej =10-2 M ; B d =10 15 G) Optical [Solid], X-ray [Dashed] Light Curves?

50 Example (M ej =10-2 M ; B d =10 15 G) Optical [Solid], X-ray [Dashed] Light Curves? Peak Luminosity L opt,peak " # $3 / 2 L sd t peak e +/- τ pairs τ ej " # $ pairs & B % 2.7 d ) ( + $ ej ' G* t peak,2 / 3 & M ej ) ( + ' 10,2 M! *,2 / 3 χ > 1 X-rays lose most of their energy to P dv work before reaching ejecta walls to be absorbed & ( ' v ej c ) + * 5 / 6

51 X-ray Excesses in Kilonova Candidates GRB B GRB Fong et al Perley et al See also Zhang 2013, Gao et al. 2013

52 Radio constraints on long-lived NS merger remnants (BDM & Bower 2013) Rotational energy eventually transferred to ISM bright radio emission (cf. Gao+13) Observed 7 short GRBs with VLA on timescales ~1-3 years after burst NO DETECTIONS rules out stable NS remnant in 2 GRBs with known high ISM densities Additional JVLA observations now much more constraining Upcoming radio surveys (e.g. ASKAP) will strongly constrain population of stable NS merger remnants indirectly probes EoS 1.4 GHz Luminosity (erg s -1 ) Rest-Frame Time Since GRB (years) Radio survey constraints 10-4 yr -1 gal -1 Frail et al. 2012

53 Timeline of Binary NS Mergers 1. Chirp enters LIGO Bandpass t (minus) ~ mins 2. Last Orbit, Plunge & Dynamical Ejecta t ~ ms 3. BH Formation ~ ms - 4. Accretion of Remnant Disk, Jet Formation (GRB) ~ s 5. He-Recombination + Disk Evaporation ~ s outflow Y e depends on NS collapse time 6. R-Process in Merger Ejecta ~ few s 7. Jet from Magnetar (X-rays) ~ min (or longer) 8. Disk Wind Kilonova prompt BH formation Y e < 0.25 (NIR, L ~ erg s -1 ) ~ week delayed BH formation Y e > 0.3 (Optical, L ~ erg s -1 ) ~ day stable magnetar (Optical, L ~ erg s -1 ) ~ day 9. Tidal Tail Kilonova (IR) ~ week 10. Ejecta ISM Interaction (Radio) ~ years Much brighter if stable magnetar

54 Workshop: March 10 - April 17, 2014 Conference: March 24-28, 2014 Equation of state of dense matter, including hyperon, kaon and quark degrees of freedom Neutrino emission and cooling of compact stars Constraints from EM observations Gravitational wave sources Models for Supernovae and for Gamma Ray Bursts Magnetars organizers: Fiorella Burgio Allessandro Drago Ian Jones Brian Metzger Pierre Pizzochero Anna Watts Registration Deadline: December 15,