CRA seminar (Dr. Michael Briggs)

Title: Gamma-ray Transients from Fermi GBM in the Multi-messenger Era

Abstract:
As the Multi-Messenger era begins with observations from IceCube and
LIGO, the Fermi Gamma-ray Burst Monitor (GBM) is well suited to provide
context observations of gamma-ray transients between 10 keV and 40 MeV.
Fermi GBM has a wide field of view, high uptime and both in-orbit
triggering and high-resolution continuous data. GBM detects numerous
gamma-ray bursts, soft gamma-ray repeaters, x-ray bursters, solar flares
and terrestrial gamma-ray flashes.    Longer timescale transients and
persistent sources are detected by the Earth occultation technique.
Using the continuous data, the GBM team has developed two ground-based
searches to enhance the detection of transients, and especially of short
gamma-ray bursts. The targeted search is initiated by a detection from
another instrument. In a Bayesian manner, the information for the other
instrument is used to coherently analyze the signals of the GBM
detectors, increasing the sensitivity to a transient. The untargeted
search agnostically searches the GBM data for all directions and times
in order to find weaker transients, especially short GRBs. This search
is finding about 80 short GRBs per year, in addition to the 40 that GBM
detects in orbit. Both searches provide results soon after the data is
available.