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The greatest flare of a Soft Gamma Repeater

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-Wind, Coronas-F, Integral, HEND, … 100 times brighter than ever!. Palmer et al. Astro-ph/0503030.

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The greatest flare of a Soft Gamma Repeater

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  1. 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-Wind, Coronas-F, Integral, HEND, … • 100 times brighter than ever! Palmer et al. Astro-ph/0503030

  2. Подборку оригинальных статейможно найти здесь:http://xray.sai.msu.ru/~polar/sci_rev/05_02_15-28.html

  3. Magnetars in the Galaxy • 4 SGRs, 8 AXPs, plus candidates, plus radio pulsars with high magnetic fields … • Young objects (about 104 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. 2001 • Problems ….. • How to generate strong bursts?

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

  6. SGRs 0526-66 1627-41 1806-20 1900+14 +candidates AXPs CXOU 010043.1-72 4U 0142+61 1E 1048.1=5937 1 RXS J170849-40 XTE J1810-197 1E 1841-045 AX J1844-0258 1E 2259+586 Known magnetars

  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 (0525-66 since 1983) Gavriil et al. 2002

  9. Historical notes • 05 March 1979. Cone experiment. Venera-11,12 (Mazets et al.) • Event in LMC. SGR 0520-66. • Fluence: about 10-3 erg/cm2 Mazets et al. 1979

  10. Main types of activity of SGRs • Weak burst. L<1041 erg/s • Intermed. bursts.L=1041–1043 erg/s • Giant bursts. L<1045 erg/s • Hyperflares. L>1046 erg/s See a review in Woods, Thompson astro-ph/0406133

  11. Common (weak) bursts from SGRS and AXPs • Typical burst from SGR 1806-29, SGR 1900+14 and from AXP 1E 2259+586 observed by RXTE (from Woods, Thompson, 2004, astro-ph/0406133) (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 1900+14 (27 Aug 1998) • Data from Ulysses (figure from Hurley et al. 1999a) • Spike 0.35 sec • P=5.16 sec • L>3 1044 erg/s • ETOTAL>1044 erg • Influenced the Earth ionosphere Hurley et al. 1999

  14. 27 Dec 2004 giant outburst of SGR 1806-20 • Spike 0.2 sec • Fluence 1 erg/cm2 • E(spike)3.5 1046 erg • L(spike)1.8 1047 erg/s • Long tail (400 s) • P=7.65 s • E(tail) 1.6 1044 erg • Distance 15 kpc

  15. Konus-Wind data om SGR 1806-20 27 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 • <5 Mpc. M82, M83, NGC 253 • About 40 Mpc. Arp 299, NGC 3256 • Possible candidates in the BATSE catalogue of short GRBs (Popov, Stern 2005)

  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)

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