Achromatic breaks for Swift GRBs. Any evidence?

Stefano Covino (INAF/OAB), Daniele Malesani (SISSA), Susanna Vergani (Dunsink), Giampiero Tagliaferri (INAF/OAB), on behalf

of the MISTICI collaboration

Venice, 6 June 2006

Zhang et al. (2006); many others…

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Ghirlanda & Ghisellini (2006)

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The prototype:

GRB 990510

Stanek et al. 2000

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Panaitescu et al. (2006); Panaitescu (talk)

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Blustin et al. (2006)

Della Valle et al. (2006)

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GRB 050801; Rykoff et al. (2006)

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short GRB 051221; Soderberg et al. (2006); Fox (talk)

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GRB 061224; Kann et al. (in preparation); Romano (talk); Curran et al. (poster)

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GRB 060526; Moretti et al. (poster); Halpern et al. (2006)

Venice, 6 June 2006

Summing up,

•most of the Swift GRBs do not show achromatic breaks;

•in a few cases, however, achromatic breaks can be singled out;

•pre-Swift: Epeak, good optical, poor X-ray coverage;

•Swift: no Epeak, X-ray coverage optimal, good optical, complex light-curves

•Future: best use of the few good events. Is it time to think to worlwide coordination for optical?

Venice, 6 June 2006