EXTRASegunda-feira – 03/12/2007 – 11h Auditório 1 – IAG/USP

Jean Heyvaerts

Observatório de Strasbourg, França

Título/Title: New-born differentially rotating magnetized quark stars as long gamma ray burst central engines

Resumo/Abstract:

New born compact objects resulting from a SN explosion are differentially rotating just after the collapse. We (Heyvaerts, Bonazzola, Bejger and Haensel) have discussed different ways by which this differential rotation, which develops into a global torsional Alfvén wave in the star, could cause a temporary post collapse activity giving rise to a long gamma ray burst. Direct electromagnetic emission in an outside vacuum or in a leptonic wind has been found to be insignificant. However, if the star oscillates in an odd mode, even of a very small amplitude, its initially closed magnetosphere can be blown open by electric currents driven in it. A relativistic leptonic wind is then emitted from the entire surface of the star, which considerably enhances its energy output. The power emitted in the form of such a wind and the life-time of this enhanced activity match the observational constraints for long gamma ray bursts if the star's magnetic field is of order of a few 10^14 Gauss.

 

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