|X-rays from Magnetars: Timing, Spectra & Polarization
Pranab Ghosh, Tata Institute for Fundamental Research
Abstract: Magnetars are neutron stars with superstrong (~ 10^14 - 10^15 G) magnetic fields, manifesting themselves as Anomalous X-ray Pulsars and Soft Gamma Repeaters. We discuss a scheme for calculating the transport of X-rays emitted by magnetars through their magnetospheres which keeps track of the timing, spectra, and polarization of the photons, and whose results are to be compared with observations from current and future space missions like NICER and IXPE. Radiation transport is handled by tracing rays in the spacetime around the neutron star and describing radiative transfer in a general-relativistic formalism, using the recent twisted magnetosphere models of magnetars. For persistent magnetar emission, we calculate light curves, soft X-ray spectra, as well as polarization fraction and angle as functions of pulse phase. For magnetar burst phenomena, we use the quasiperiodic oscillations observed during the bursts as complementary probes of the structure and dynamics of magnetar magnetospheres with the aid of NICER data.
|Date||October 26, 2017|
|Start/End Time||12:00 PM - 01:00 PM|
|Location||Building 34, Room E215|
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