Close Binary Progenitors Of Gamma Ray Bursts And Hypernovae Maxim - PowerPoint PPT Presentation

Close Binary Progenitors Of Gamma Ray Bursts And Hypernovae Maxim Barkov MPI-K Heidelberg, Germany Space Research Institute, Russia Serguei Komissarov University of Leeds, UK 30/06/2011 30/06/2011 HEPRO-III, Barcelona 1

Plan of this talk • Gamma-Ray-Bursts – very brief review, • Models of Central Engines, • Numerical simulations I: Magnetic flux, • Magnetic Unloading, • Realistic initial conditions, • Numerical simulations II: Collapsar model, • Common Envelop and X-Ray flares, • Fast Recycling of Neutron Star as Hypernova engine, • Conclusions 30/06/2011 30/06/2011 HEPRO-III, Barcelona 2

I. Gamma-Ray-Bursts Discovery: Vela satellite (Klebesadel et al.1973); Konus satellite (Mazets et al. 1974); Cosmological origin: 1. Beppo-SAX satellite – X-ray afterglows (arc-minute resolution) , optical afterglows – redshift measurements – identification of host galaxies (Kulkarni et al. 1996, Metzger et al. 1997, etc) ‏ 2. Compton observatory – isotropic distribution (Meegan et al. 1992); Supernova association of long duration GRBs: 1. Association with star-forming galaxies/regions of galaxies; 2. A few solid identifications with supernovae, SN 1998bw, SN 2003dh and others... 3. SN humps in light curves of optical afterglows. 4. High-velocity supernovae ( 30,000km/s) or hypernovae (10 52 erg). 30/06/2011 30/06/2011 HEPRO-III, Barcelona 3

Spectral properties: Non-thermal spectrum from 0.1MeV to GeV: Bimodal distribution (two types of GRBs?): long duration GRBs short duration GRBs very long 30/06/2011 30/06/2011 HEPRO-III, Barcelona 4 duration GRBs

Variability: • smooth fast rise + decay; • several peaks; • numerous peaks with substructure down to milliseconds Total power: assumption of isotropic emission Inferred high speed: Too high opacity to unless Lorentz factor > 100 30/06/2011 30/06/2011 HEPRO-III, Barcelona 5

The possible scenario of GRB formation in close binary system with BH: 30/06/2011 HEPRO-III, Barcelona 7

II. Relativistic jet/pancake model of GRBs and afterglows: jet at birth pancake later (we are here) 30/06/2011 30/06/2011 HEPRO-III, Barcelona 8

Merge of compact stars – origin of short duration GRBs? Paczynsky (1986); Goodman (1986); Eichler et al.(1989); Neutron star + Neutron star Black hole + compact disk Neutron star + Black hole White dwarf + Black hole Burst duration: 0.1s – 1.0s Released binding energy: 30/06/2011 30/06/2011 HEPRO-III, Barcelona 9

Collapsars – origin of long duration GRBs? Woosley (1993) ‏ Iron core collapses into a black hole: MacFadyen & Woosley (1999) ‏ “failed supernova”. Rotating envelope forms hyper-accreting disk Collapsing envelope Accretion disk Accretion shock The disk is fed by collapsing envelope. Burst duration > a few seconds 30/06/2011 30/06/2011 HEPRO-III, Barcelona 10

Mechanisms for tapping the disk energy Neutrino heating Magnetic braking fireball MHD wind B B Eichler et al.(1989), Aloy et al.(2000) Blandford & Payne (1982) ‏ MacFadyen & Woosley (1999) Proga et al. (2003) ‏ Nagataki et al.(2006), Birkl et al (2007) Fujimoto et al.(2006) ‏ Zalamea & Beloborodov (2008,2010) (???) ‏ Mizuno et al.(2004) 30/06/2011 30/06/2011 HEPRO-III, Barcelona 11

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III. Numerical simulations Setup (Barkov & Komissarov 2008a,b) (Komissarov & Barkov 2009) Uniform magnetization black hole R=4500km M=3M sun Y = 4x10 27 -4x10 28 Gcm -2 a=0.9 Rotation:     2 3 sin min / , 1 l l r r 0 c r c =6.3x10 3 km v l 0 = 10 17 cm 2 s -1 B v v • 2D axisymmetric v GRMHD; v • Kerr-Schild metric; • Realistic EOS; B • Neutrino cooling; outer boundary, free fall • Starts at 1s from R= 2.5x10 4 km accretion collapse onset. (Bethe 1990) Lasts for < 1s 30/06/2011 30/06/2011 HEPRO-III, Barcelona 13

Free fall model of collapsing star (Bethe, 1990) ‏ radial velocity: mass density:  1 / 2   1   t M      accretion rate:   1 M 0 . 1 C M s   1 sun     1 s 10 M sun Gravity: gravitational field of Black Hole only (Kerr metric); no self-gravity; Microphysics: neutrino cooling ; realistic equation of state, (HELM, Timmes & Swesty, 2000); dissociation of nuclei (Ardeljan et al., 2005); Ideal Relativistic MHD - no physical resistivity (only numerical); 30/06/2011 30/06/2011 HEPRO-III, Barcelona 14

Model:A unit length=4.5km t=0.24s C 1 =9; B p =3x10 10 G log 10  (g/cm 3 ) log 10 B  /B p log 10 P/P m magnetic field lines, and velocity vectors 30/06/2011 30/06/2011 HEPRO-III, Barcelona 15

Model:A unit length=4.5km t=0.31s C 1 =9; B p =3x10 10 G log 10  (g/cm 3 ) magnetic field lines, and velocity vectors 30/06/2011 30/06/2011 HEPRO-III, Barcelona 16

Jets are powered mainly by the black hole via the Blandford-Znajek mechanism !! Model: C • No explosion if a=0; • Jets originate from the black hole; • ~90% of total magnetic flux is accumulated by the black hole; • Energy flux in the ouflow ~ energy flux through the horizon (disk contribution < 10%); • Theoretical BZ power:        Y   50 2 2 51 1 3 . 6 10 0 . 48 10 E BZ f a M erg s 27 2 30/06/2011 30/06/2011 HEPRO-III, Barcelona 17

    17 2 1     l 10 cm s 1 M 0 . 15 M s C 3 0 SUN 1    10 a 0 . 9 B 0 . 3 10 G   P log 10    ( ) g log P 10   m 30/06/2011 30/06/2011 HEPRO-III, Barcelona 18

IV. Magnetic Unloading What is the condition for activation of the BZ-mechanism ? 1) MHD waves must be able to escape from the black hole ergosphere to infinity for the BZ-mechanism to operate, otherwise accretion is expected. or 2) The torque of magnetic lines from BH should be sufficient to stop      2 / 1 (???) E BZ M c accretion   (Barkov & Komissarov 2008b)    Y  50 2 2 E BZ 3 . 6 10 f a M 27 2 (Komissarov & Barkov 2009) 2   a    f a 2   2 1 1 a 30/06/2011 30/06/2011 HEPRO-III, Barcelona 20

The disk accretion relaxes the explosion      conditions. The MF lines’ shape reduces 2 E BZ / M c 1 / 10 the local accretion rate. 30/06/2011 30/06/2011 HEPRO-III, Barcelona 21

V. Realistic initial conditions • Strong magnetic field suppresses the differential rotation in the star (Spruit et. al., 2006). • Magnetic dynamo can’t generate a large magnetic flux, a relict magnetic field is necessary. (see observational evidences in Bychkov et al. 2009) • In close binary systems we could expect fast solid body rotation. • The most promising candidate for long GRBs is Wolf-Rayet stars. 30/06/2011 30/06/2011 HEPRO-III, Barcelona 22

Simple model: Barkov & Komissarov (2010) R star If l(r)<l cr then matter falling to BH directly If l(r)>l cr then ( r ) matter goes to disk l and after that to BH BH Agreement with model Shibata&Shapiro (2002) on level 1% 30/06/2011 30/06/2011 HEPRO-III, Barcelona 23

Power low density distribution model    r 3 30/06/2011 30/06/2011 HEPRO-III, Barcelona 24

Realistic model Heger at el (2004) M=35 M sun , M WR =13 M sun 30/06/2011 30/06/2011 HEPRO-III, Barcelona 25

Realistic model Realistic model Heger at el (2004) M=20 M sun , M WR =7 M sun M=35 M sun , M WR =13 M sun neutrino limit BZ limit 30/06/2011 30/06/2011 HEPRO-III, Barcelona 26

VI. Numerical simulations II: Collapsar model GR MHD Setup 2D black hole M=10 M sun Bethe’s v a=0.45-0.6 free fall model, B T=17 s, C 1 =23 v v v Dipolar v magnetic field Initially solid B body rotation Uniform magnetization R=150000km Barkov & Komissarov (2010) B 0 = 1.4x10 7 -8x10 7 G 30/06/2011 30/06/2011 HEPRO-III, Barcelona 27

In some cases (30%) one side jets are formed. 30/06/2011 HEPRO-III, Barcelona 28

a=0.6 Ψ =3x10 28 a=0.45 Ψ =6x10 28     E 10 M       1 sun V 170 km s     kick 52     10 ergs M bh Ψ 28 dM BH /dt η Model a B 0,7 L 51 A 0.6 1 1.4 - - - B 0.6 3 4.2 0.44 0.017 0.0144 C 0.45 6 8.4 1.04 0.012 0.049 30/06/2011 30/06/2011 HEPRO-III, Barcelona 29

VII Common Envelop (CE): few Normal WRS seconds black hole spiralling And Black Hole < 1000 seconds disk formed MBH left behind 5000 seconds jets produced 30/06/2011 30/06/2011 HEPRO-III, Barcelona 30