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The 2009 Fermi Symposium

Suzaku X-ray Observations of New Gamma-ray Pulsars Discovered by Fermi LAT

Nobuyuki Kawai, Tokyo Institute of Technology


The Fermi LAT has newly discovered 16 pulsars starting with the one associated with supernova remnant CTA 1. It is of interest to examine whether these pulsars discovered only in gamma-rays are intrinsically different from the known radio pulsars for which gamma-ray emission is detected with LAT. Alternatively, these gamma-ray discovered pulsars may belong to the same class viewed with different geometries in which narrow radio beams are missed. We therefore have started X-ray counterpart searches using Suzaku. With these observations, we found possible counterparts for most of the targets. In the model fitting of their X-ray energy spectra, power-law components are necessary, suggesting their origins in non-thermal magnetospheric emission of neutron stars and/or synchrotron emission of pulsar wind nebulae. Distribution of X-ray photon indices are consistent with that of known radio-selected gamma-ray pulsars. We also find no significant difference in the ratio bet! ween the estimated X-ray luminosity and the spin-down luminosity for the gamma-ray discovered and radio-selected pulsars.