Swift 1644+57: The Longest Gamma-ray Burst?

摘要: Swift recently discovered an unusual gamma-ray and x-ray transient (Sw 1644+57) that was initially identified as a long-duration burst (GRB). However, the 10 keV emission has persisted for over month with luminosity comparable to its peak value. The astrometric coincidence of source center host galaxy, together other considerations, motivated interpretation Sw 1644+57 produced by outburst from 6 7 M black hole at galaxy. Here we consider alternate possibility is indeed GRB, albeit particularly long one! We discuss general properties very long-duration, low-power GRB-like transients associated core-collapse massive star. Both neutron star (magnetar) spindown accretion can power such events. requirements producing low-power, GRBs magnetar are similar those powering extremely luminous supernovae spindown, suggesting possible connection between these two types transients. Alternatively, could be faintest explosions: collapse rotating red supergiant in nominally failed supernova onto solar-mass up 100 days; jet inevitably unbinds outer envelope progenitor, leading weak 49 erg explosion. In both models, burrow through few days, kinetic 45 46 s 1 , su cient observed 1644+57.