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GRB GReat Bu’s GRB 2004 / 112 Early Mission History 1960s, the Vela series Burst And Transient Source Experiment (on the CGRO, launched in 1991) BeppoSAX (launched in 1996/4/30)– provide a much more accurate location HETE– failed in 1996 GRB910421 1967/7/2 the first observation 1973 publish “Model burst” Distance: 1)galactic disc 2)halo 3)cosmological ~102pc ~104pc ~Mpc For now 1)isotropic distribution 2)redshift determination(~30 now) 3)Angular distrubution strong suggest a cosmological origion!! Z-known GRBs So…. Huge energy Eiso~1051-54 erg Rapid temporal variability on time scales of ms compact object However, due to γ+γ e+ + eoptical depth should be >> 1, non-thermal spectrum optical thin Compactness problem The “fire ball” Large concentration of electromagnetic radiation in small region of space with small fraction of baryons Sudden release of high intensity gammarays produces e+e- pairs which create an opaque photon-lepton “fireball” The solution?? The relativistic motion ( with Γ≧100 ) of the emitting region GRB are produced when an UR energy flow is converted to radiation in an optically thin region aberration of light : cos ' cos 1 v cos ' beaming effect : for 1, 1 ~ GRB all star GRB970228 Afterglow, x-ray ,optical counterpart, XT RT (a breakthrough) GRB970508 Redshift ,absorption lines (FeII MgII), radio counterpart GRB971214 Host galaxy GRB980425 SN association(SN1998bw) (z=0.0085, the “closet”) GRB990123 most energetic ( Eiso~3 X 1054erg ) optical counterpart (by ROTSE) GRB030325 polarzation GRB030329 SN association(SN2003dh) m1 1 m2 2 (m1 m2 m E ) C2 Adopt from SCIENCE@NASA Summary of observation Observation (I) --GRB Eiso Burst rate in 1991-2000 (CGRO operation period) 1/day (~1/106-7yr/galaxy) Duration T90:5%~95% in the 50-300keV Observation (II) --GRB Spectrum Non-thermal No clear observational evidence for the existence of spectral lines Observation (III) -afterglow Lightcurves Well fitted by power-laws ~5 GRB has line features in the early Xray afterglow Some of them “Break” (low energy poewer index ~2) Offset from the center of the hot galaxy Host galaxy (025~Z~4.5): are typically low mass, faint galaxies (R~25) with active star formation region several re-brightenings, varying power law indices Observation (IV) -afterglow GRB/SN connection red excess ,”SN bump”: GRB980326, GRB011121 GRB980425 / SN1998bw : within the error box GRB030329 / SN2003dh: very similar spectrum with that in SN1998bw case “super” Type Ic Types of SNe according to the spectrum with H = SN II without H = SN I with Si = SN Ia without Si but with He = SN Ib without Si and without He = SN Ic The energy source for SN Ia is nuclear; for the others is gravitational The lack of a measured redsift SNIc Best fit : Z~0.95 Spectral evolution Observation (V) -afterglow Polarization MNRAS 309,L7 1999 Consider a magnetic field completely tangled in the plane of the shock front, but with a high degree of coherence in the orthogonal direction Γ 1 light aberration vanishes, The observe magnetic field is Completed tangled and Polarization disappears Γ ~ 1/(θc+ θ0) Γ <1/(θc- θ0) see only part of the circle centred on θ0 Γ >>1, no polarization Two maxima in the polarization light curve, the first for The horizontial component and the second for the vertical one!! GRB030325 Oh , Theory Model forest SGRs as a hint ?? Relativistic dust crash energetically into the solar wind Comets falling onto NSs Precessing jets from pulsars Canonballs from supernovae Jet-disk in a binary system Magnetar bubble collapse NS collapse to a strange star Collapse to a BH caused by accretion Supermassive BH formation Evaporating BHs The “fireball” again GRBs occur through the dissipation of the kinetic energy of a relativistic expanding fire ball γ-ray emission mechanisms The shape of things Time variability (~milliesecond) R~ CΓ∆T compact object Duration 10-2s ~ 103s Energy Eiso~1051-54 (for z-known GRBs) Beaming Rates , R~1/106-7yr/galaxy if beamed….. E jet ~ Eiso 2 2 j j : half - opening angle j 2 4 R' R , 2 sin d d 0 0 The internal-external model Time-varying outflow makes different Γ(>100) shells When a faster shell catch up with a slower one: Kinetic energy internal energy (internal shock ) radiation (accelerated electrons interact with the ambient magnetic field ) internal shock GRB external forward shock afterglow The “inner engine” Binary NS merge WD-NS , NS-BH merge failed supernova (Collapsar) Collapsar – a BH is born 1993, by Woosley et al. “Failed supernova” Iron core collapse BH MHD jet ApJ 524:262 1999 Adopted from GSFC, NASA The jet is erupting through the surface of the star. Blue represents regions of low mass concentration, red and yellow are denser . Note the blue and red striations behind the head of the jet. These are bounded by internal shocks. Make story complete — asymmetric supernova 2000, by wheeler et al. The generation of jets Make story more complete — Wolf-Reyet star Wolf-Rayet stars are hot (25-50,000+ degrees K), massive stars (20+ solar mass) with a high rate of mass loss. Strong, broad emission lines (with equivalent widths up to 1000Å!) arise from the winds of material being blown off the stars. Wolf-Rayets stars are divided into 3 classes based on their spectra, WN stars (nitrogen dominant, some carbon), WC stars (carbon dominant, no nitrogen), WO stars with C/O < 1. The whole story…. To make a collapsar need three essential components: 1)Wolf-Rayet star 2)A rotating stellar core 3)A core collapse that failed to produce a successful supernova Summary Conclusion Multi-origion MHD Gravitational wave Polarization TeV photon observation GRB 970828 no OT, “dark burst” be obscured by dust in their host galaxy associated with massive sar formation?? The unified model?? astro-ph/0410728 Reference and Special Thanks Many of content are adopted from “Jochen Greiner Homepage” ( http://www.mpe.mpg.de/~jcg/ ) Romanian Report in Phisics, Vol.56 No.2 P204, 2004 Valeriu Tudose et al. ASTRONOMY, October 2004 Others….