Prof. Matthew Baring (Rice Univ.) visit our group and give colloquium speech

Dec 9, 2011

“The Quiescent and Flaring Emission of Magnetars”

 

Magnetars are the most powerful compact objects in the stellar mass range observed in the Milky Way.  The initial spikes of giant flares seen in three soft gamma repeaters (SGRs) dwarf the fluxes of the brightest cosmological gamma-ray bursts.

Periodicity seen in magnetar quiescent and outburst emission, and distinctive “spin-down” lengthening of the period have driven the paradigm that strongly-magnetized neutron stars constitute these fascinating sources.  This talk summarizes properties of both quiescent and outburst emission in magnetars, and some dissipative processes in their magnetospheres, including Comptonization.  It discusses the action and characteristics of resonant Compton upscattering in generating hard X-ray tails of magnetars, and also possible signatures of exotic mechanisms like photon splitting. The recent suggestion of possible photospheric radius expansion in the newly-discovered magnetar SGR 0501+4516 as an interpretation of Fermi-GBM light curves will also be briefly addressed.