Fast Radio Bursts

Jonathan Katz (Washington University) - October 31, 2016 at 12:10 pm

Fast Radio Bursts are brief (<1 ms to ~10 ms) bursts observed at ~1 GHz with pulse dispersions indicative of "cosmological" (z=0.5-1) distances. 17 FRB have been published, including one repeater. Their brightness temperatures approach 10^{37} K, requiring coherent emission. If isotropic, their radiated powers are as large as 10^{43} ergs/s, remarkable for objects whose light-crossing scales may be <3x10^7. No FRB has been persuasively identified with any other object. The only astronomical phenomena with such short time scales are radio pulsars and the rising phases of Soft Gamma Repeaters.
This combination of properties points to neutron stars as the origin of FRB. A fortuitous observation during the outburst of SGR 1806-20 did not find a simultaneous FRB, apparently excluding an FRB origin of SGR. If FRB are produced by pulsars, their radiated power appears to require an extraordinary combination of high magnetic field and high spin rate. However, if FRB are produced by collimated continuous emission rather than impulsive isotropic emission these constraints are relaxed.

The seminar will be held in 131A Campbell Hall.

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