10–13 Aug 2011
AlbaNova University Center
Europe/Stockholm timezone

New insights on the long GRBs-SNe association

10 Aug 2011, 18:30
5m
Oskar Klein (AlbaNova University Center)

Oskar Klein

AlbaNova University Center

Speaker

Dr Omer Bromberg (Racah Institute of Physics, The hebrew University, Jerusalem, Israel)

Description

According the Collapsar model long GRBs (LGRBs) arise during the collapse of a massive star and involve the emergence of a relativistic jet through the envelope of the exploding star. This model naturally explains the links between LGRBs and SNe, such as the the association of half a dozen LGRBs with broad-line Ic SNe. However, a closer look at this association reveals that four out of the six bursts differ form ordinary LGRBs: They are less luminous, have a smooth lighcurve and their spectra show no evident for a high energy tail. The nature of these low luminosity GRBs is puzzling, and it is interesting to see whether they originate in the same way as LGRBs. We examine the propagation of a relativistic jet inside a stellar envelope, and find that the jets involved in low luminosity GRBs are not powerful enough to break out of their progenitors. This implies that their gamma-ray emission must be generated by a different mechanism than that of luminous LGRBs. The high rate of the low luminosity GRBs indicates that jets that are generated following a core collapse, have a higher chance of being buried rather than breaking out. This puts the GRB-SN connection in a new light where typical SNe engines can only generate low luminosity GRBs while only the most powerful ones can generate LGRBs.

Primary author

Dr Omer Bromberg (Racah Institute of Physics, The hebrew University, Jerusalem, Israel)

Co-authors

Dr Ehud Nakar (Tel Aviv University, Israel) Prof. Tsvi Piran (Racah Institute of Physics, The hebrew University, Jerusalem, Israel)

Presentation materials

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