The greatest flare of a Soft Gamma Repeater On December 27 2004 the greatest flare from SGR 1806-20 was detected by many satellites: Swift, RHESSI, Konus- - презентация

1 The greatest flare of a Soft Gamma Repeater On December the greatest flare from SGR was detected by many satellites: Swift, RHESSI, Konus- Wind, Coronas-F, Integral, HEND, … 100 times brighter than ever! Palmer et al. Astro-ph/

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3 Magnetars in the Galaxy 4 SGRs, 8 AXPs, plus candidates, plus radio pulsars with high magnetic fields … Young objects (about 10 4 yrs). Probably about 10% of all NSs.

4 Alternative theory Fossil disk Mereghetti, Stella 1995 Van Paradijs et al.1995 Alpar 2001 Marsden et al Problems ….. How to generate strong bursts?

5 Why magnetars? dE/dt > dE rot /dt By definition: magnetically-powered NSs P-Pdot Direct field measurements (Ibrahim et al.)

6 Known magnetars SGRs candidates AXPs CXOU U E = RXS J XTE J E AX J E

7 Magnetic field measurements Direct measurement of the magnetic field of the SGR Spin-down Long periods Ibrahim et al. 2002

8 Are SGRs and AXPs relatives? SGR-like bursts from AXPs Spectral properties Quiet periods of SGRs ( since 1983) Gavriil et al. 2002

9 Historical notes 05 March Cone experiment. Venera-11,12 (Mazets et al.) Event in LMC. SGR Fluence: about erg/cm 2 Mazets et al. 1979

10 Main types of activity of SGRs Weak burst. L

11 Common (weak) bursts from SGRS and AXPs Typical burst from SGR , SGR and from AXP 1E observed by RXTE (from Woods, Thompson, 2004, astro-ph/ ) (from Woods, Thompson 2004)

12 Intermediate SGR bursts Four intermediate bursts. However, the forth is sometimes considered as a giant one (from Woods, Thompson) (from Woods, Thompson 2004)

13 Giant flare from SGR (27 Aug 1998) Data from Ulysses (figure from Hurley et al. 1999a) Spike 0.35 sec P=5.16 sec L> erg/s E TOTAL >10 44 erg Influenced the Earth ionosphere Hurley et al. 1999

14 27 Dec 2004 giant outburst of SGR Spike 0.2 sec Fluence 1 erg/cm 2 E(spike) erg L(spike) erg/s Long tail (400 s) P=7.65 s E(tail) erg Distance 15 kpc

15 Konus-Wind data om SGR Dec 2004 flare Mazets et al. 2005

16 SGR giant flares vs. GRBs Woods et al.

17 SGRs and starformation Possibility of a SGR detection outside the Local group of galaxies Starforming galaxies are the best sites for a search

18 Theory of magnetars Thompson, Duncan ApJ 408, 194 (1993) Entropy-driven convection in young NSs generate strong magnetic field Twist of magnetic field lines

19 Magnetars origin (a speculative discussion) Fast rotation is necessary (Thompson, Duncan) Spin-up of a progenitor star in a binary via accretion or synchronization Coalescence About 10% of NSs (Popov, Prokhorov 2005)