Fermi Observations of short-hard GRB 090510
Abstract
GRB 090510 is a bright, short-hard Gamma-ray Burst (GRB), which triggered both Large Area Telescope (LAT) and Gamma-ray Busrt Monitor (GBM) onboard Fermi. This is the first GeV short GRB with known redshift. The delayed onset and long-lived behavior of the high energy photon of the LAT were also seen by this GRB as well as many other LAT GRBs.
A broad-band spectroscopy by the LAT and GBM revealed an additional spectral component against to the traditional Band function, which is the first evidence of the extra component from short GRB. A 31 GeV photon, the highest energy photon from short GRB was detected 0.83 s after the onset of the GRB. This enables us to set the largest lower limit on the bulk Lorentz factor of the outflow for any GRBs assuming that the LAT 31 GeV photon is associated with the narrow spike observed with the GBM. The delayed emission of the LAT 31 GeV photon supports Lorentz invariance, and disfavors quantum-gravity theories in which a postulated granularity of space-time on a very small scale alters the speed of light, giving it a linear dependence on photon-energy.- Publication:
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AAS/High Energy Astrophysics Division #11
- Pub Date:
- March 2010
- Bibcode:
- 2010HEAD...11.1407O