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Gamma ray bursts and supernovae G.S.Bisnovatyi-Kogan IKI RAS and MEPHI

Gamma ray bursts and supernovae G.S.Bisnovatyi-Kogan IKI RAS and MEPHI. MEPHI School, 24 September, 2010. Neutron star magnetic fields Radiopulsars. Magnetorotational supernovae GRB, SGR Naked eye optical afterglow Magnetars Nuclear model of SGR.

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Gamma ray bursts and supernovae G.S.Bisnovatyi-Kogan IKI RAS and MEPHI

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  1. Gamma ray bursts and supernovae G.S.Bisnovatyi-Kogan IKI RAS and MEPHI . MEPHI School, 24 September, 2010

  2. Neutron star magnetic fields Radiopulsars. Magnetorotational supernovae GRB, SGR Naked eye optical afterglow Magnetars Nuclear model of SGR

  3. Neutron stars are the result of collapse. Conservation of the magnetic flux B(ns)=B(s) (R /R ) B(s)=10 – 100 Gs, R ~ (3 – 10) R(Sun), R =10 km B(ns) = 4 10 – 5 10 Gs Ginzburg (1964)

  4. Radiopulsars E = AB - magnetic dipole radiation (pulsar wind) E = 0.5 I I – moment of inertia of the neutron star B = IPP/4 A Single radiopulsars – timing observations (the most rapid ones are connected with young supernovae remnants) B(ns) = 2 10 – 5 10 Gs

  5. Explosion mechanisms of • spherically symmetric star • Thermonuclear explosion of C-O degenerate core (SN Ia) • 2. Core collapse and formation of a neutron star, neutrino deposition • gravitational energy release up to 5 10 erg, carried away by neutrino (SN II, SN Ib,c) Equal to binding energy of the neutron star

  6. Most of supernova explosions and ejections are not spherically symmetrical. A lot of stars arerotating and have magnetic fields. Often we can see one-side ejections. Magnetorotational mechanism: transforms rotational energy of the star to the explosion energy. In the case of the differential rotation the rotational energy can be transformed to the explosion energy by magnetic fields. .

  7. Soviet Astronomy, Vol. 14, p.652 (1971) The Explosion of a Rotating Star As a Supernova Mechanism. G.S.Bisnovatyi-Kogan

  8. The magnetohydrodynamic rotational model of supernova explosion Astrophysics and Space Science, vol. 41, June 1976, p. 287-320 Calculations of supernova explosion are made using the one-dimensional nonstationary equations of magnetic hydrodynamics for the case of cylindrical symmetry. The energy source is supposed to be the rotational energy of the system (the neutron star in the center and the surrounding envelope). The magnetic field plays the role of a mechanism of the transfer of rotational momentum. The calculations show that the envelope splits up during the dynamical evolution of the system, the main part of the envelope joins the neutron star and becomes uniformly rotating with it, and the outer part of the envelope expands with large velocity, carrying out a considerable part of rotational energy and rotational momentum. These results correspond qualitatively with the observational picture of supernova explosions.

  9. alpha=0.01, t=8.5 1-D calculations of magnetorotational explosion .

  10. The main results of 1-D calculations: Magneto-rotational explosion (MRE) has an efficiency about 10% of rotational energy.For the neutron star mass the ejected mass  0.1М,Explosion energy 1051 ergEjected mass and explosion energy depend very weekly on the parameter Explosion time strongly depends on  . tвзрыва~ Explosion time = • Small is difficult for numerical calculations with EXPLICIT numerical schemesbecause of the Courant restriction on the time step, “stiff” system of equations: • determines a “stiffness”. In 2-D numerical IMPLICIT schemes have been used.

  11. Difference scheme(Ardeljan, Chernigovskii, Kosmachevskii, Moiseenko) Lagrangian, on triangular reconstructing grid, implicite, fully conservative Ardeljan N.V,Kosmachevskii K.V., Chernigovskii S.V., 1987, Problems of construction and research of conservative difference schemes for magneto-gas-dynamics, MSU, Moscow (in Russian) Ardeljan N.V, Kosmachevskii K.V. 1995, Computational mathematics and modeling, 6, 209 Ardeljan N.V., Bisnovatyi-Kogan G.S., KosmachevskiiK.V., Moiseenko S.G., 1996, Astron. Astrophys. Supl.Ser., 115, 573

  12. Grid reconstruction (example)

  13. Initial State Spherically Symmetric configuration, Uniform rotation with angular velocity 2.519 (1/сек). Temperature distribution: + 20%Grid Density contours

  14. Maximal compression state

  15. Shock wave does not produce SN explosion :

  16. Distribution of the angular velocity The period of rotation at the center of the young neutron star is about 0.001 sec

  17. 2-D magnetorotational supernova N.V.Ardeljan, G.S.Bisnovatyi-Kogan, S.G.Moiseenko MNRAS, 359, 333 (2005) A magnetorotational core-collapse model with jets S. G. Moiseenko,G. S. Bisnovatyi-Koganand N. V. ArdeljanMNRAS 370, 501 (2006) Equations: MHD + self-gravitation, infinite conductivity. Axial symmetry () , equatorial symmetry (z=0).

  18. Initial toroidal current Jφ (free boundary) Biot-Savarat law

  19. Initial magnetic field –quadrupole-like symmetry

  20. Toroidal magnetic field amplification. pink – maximum_1 of Hf^2 blue – maximum_2 of Hf^2 Maximal values of Hf=2.5 10(16)G The magnetic field at the surface of the neutron star after the explosion is H=4 1012 Gs

  21. Temperature and velocity field Specific angular momentum

  22. Neutron star formation N.V.Ardeljan, G.S.Bisnovatyi-Kogan, S.G.Moiseenko MNRAS, 2005, 359, 333. B(chaotic) ~ 10^14 Gs High residual chaotic magnetic field after MRE core collapse SN explosion. Heat production during Ohmic damping of the chaotic magnetic field may influence NS cooling light curve

  23. Particle is considered “ejected” if its kinetic energy is greater than its potential energy (alpha=10^{-6}) Ejected energy Ejected mass 0.14M 0.6 10 эрг

  24. Magnetorotational explosion at different

  25. Magnetorotational instabilityexponential growth of magnetic fields. Dungey 1958,Velikhov 1959, Spruit 2002, Akiyama et al. 2003

  26. Inner region: development of magnetorotational instability (MRI)

  27. Toy model of the MRI development: expomemtial growth of the magnetic fields at initial stages MRI leads to formation of multiple poloidal differentially rotating vortexes. Angular velocity of vortexes is growing (linearly) with a growth of H.

  28. Jet formation in MRE Moiseenko et al. Astro-ph/0603789 Dipole-like initial magnetic field

  29. Violation of mirror symmetry of magnetic field (Bisnovatyi-Kogan, Moiseenko, 1992 Astron. Zh., 69, 563 (SvA, 1992, 36, 285) • Initial toroidal field • Initial dipole field • Generated toroidal field • Resulted toroidal field

  30. S. Johnston et al. astro/ph 0510260 (MNRAS, 2005, 364, 1397) Evidence for alignment of the rotation and velocity vectorsin pulsars We present strong observational evidence for a relationship between the direction of a pulsar's motion and itsrotation axis. We show carefully calibrated polarization data for 25pulsars, 20 of which display linearly polarized emission from the pulselongitude at closest approach to the magnetic pole… we conclude that the velocity vector and the rotation axis arealigned at birth. W.H.T. Vlemmings et al. astro-ph/0509025 (Mm. SAI, 2005, 76, 531) Pulsar Astrometry at the Microarcsecond Level Determination of pulsar parallaxes and proper motionsaddresses fundamental astrophysical questions. We have recentlyfinished a VLBI astrometry project to determine the proper motions andparallaxes of 27 pulsars, thereby doubling the total number of pulsarparallaxes. Here we summarize our astrometric technique and presentthe discovery of a pulsar moving in excess of 1000 kms, PSRB1508+55.

  31. (around 1 MeV) GRB from SN explosion: Bisnovatyi-Kogan, Imshennik, Nadyozhin, Chehchetkin(1975) X-rays (Beppo-SAX), optical telescope, HST Collimation is needed to decrease the energy

  32. GRB CENTRAL MACHINE MODELS Hypernova (very powerful supernova). Paczynski (1998) – explosion of a helium star (see also Blinnikov and Postnov, 1998) Usov (1992) – new born pulsar, veryrapid, with high magnetic field Cherepashchuk, Gershtein et al. (2002) W-R stars as GRB predecessors Woosley et al. (2001) collapse of very massive star, formation of a black hole with a massive disk (may be with magnetic field) Now it is the most popular model. Traces of SNe are belived to be found in optical afterglows of several GRB. (Barkov, Komissarov, 2007)

  33. The inner region at t = 0:45s. Left panel: the magnetization parameter, log_10(P/P_m), and the magnetic field lines; Middlepanel: the ratio of azimuthal and poloidal magnetic field strengths, log_10(B_phi/B_p), and the magnetic field lines; Right panel: the magnetic field strength, log_10(B), and the magnetic field lines.

  34. 4. Magnetized disk around rotating (Kerr) black hole (RBH) Van Putten (2001). Extraction of rotational energy of RBH when magnetic field is connecting the RBH with the surrounding accretion disk or accretion torus: Blandford—Znajek mechanism.5. Vacuum explosion by strongly charged Black Hole Ruffini (2000). Problems with formation of such strongly charged black hole.6. GRB from superconducting strings, Berezinsky at al., PR D (2001), 64, 0430047. Transition from neutron star to quark star, Berezhiani et al. astro-ph/02-09-257

  35. About 4000 gamma ray bursts had been discoveredlong and short GRB

  36. High redshifts, up to Z ~ 6, optical afterglows, GRB-SN connections – only by long GRB. • Origin may be different (still not known for both types)

  37. Stanek et al.,astro-ph/0304173

  38. Hjorth et al., astro-ph/0306347 Spectral evolution of the combined optical flux density, of theafterglow of GRB030329, the associated SN2003dh, and its host galaxy.

  39. AFTERGLOW FROM THE HEATED GAS The magnitudes of the counterparts (upper limit - solid line, lower limit - dashed line) as a function of time after burstfor GRB with total flux near the Earth F{GRB} = 10^{-4} erg/cm^2: 1a. - for the case E = 10^{52} erg; n_0= 10^5 cm^{-3}; 1b - for the case E = 10^{51} erg; n_0= 10^5 cm^{-3} (B.-K., Timokhin, 1997)

  40. Temperature distribution in the part of non-uniform cloud with N_max=10^-5, (low-density cone) in the cone after GRB with isotropic energy output 10^52erg, Barkov (2004), PhD. 0 Barkov, Bisnovatyi-Kogan: astro/ph 0410186

  41. Prompt Optical Emission. GRB990123 about 100 s. T(50%)=30 s. T(90%)=63 s. F(BATSE)=5.1 10-4 erg/cm2 ASCA 2-10 keV, 55 h , 10-12 erg/cm2 /s OSSE < 10MeV; COMPTEL 0.2-30 MeV (46 s.) Beppo-SAX - Localization Optics: ROTSE, Los Alamos, t > 22.18 s after beginning of GRB Unfiltered light Jan 24, 40 min. KECK spectrum (optical) Lines: Mg II, Si II, Fe II, Zn II, C IV, Al II, Fe II … Redshift: z=1.61 Q(gamma)>2.3 1054 erg L(opt) > 2 1016 Solar Luminosity = 8 1049 erg/s Radio: VLA 8.46 GHz about 260 microJansky; Westerbork 4.88 GHz < 130 microJansky; Jan. 24.4, 15 GHz – NO FLUX GRB 021004 (15m, z=2.3) GRB 030329 (12.4m, z=0.168) GRB 030418 (16.9m )

  42. Search of rapid optical transients in wide fields SAO Field of view – 400-600 sq. grad Time resolution– 0.13 sec Limiting value – 10 – 11.5m Ammount of data – 600 Gb/night Pozanenko (IKI), Beskin (SAO), Bondar (NIIPP) Data analysis in real time scale Camera FAVOR - NIIPP, SAO, IKI

  43. TORTOREM = Tortora + REM La Silla, In automatic regime since May, 2006

  44. KONUS

  45. Tortora

  46. Tortora

  47. Prompt optical emission is strongly correlated with gamma • May be it has the same collimation, as gamma radiation. • Optical afterglows (at longer times) should not be collimated.

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