Fermi Gamma-ray Space Telescope

A Search for Candidates of Variable Gamma-ray Pulsars

C. H. Wu
C. Y. Hui, K. H. Kong

Abstract:

We present preliminary results of a method to search for candidates of variable gamma-ray pulsars with Fermi-LAT. Gamma-ray pulsars are usually defined as steady gamma-ray sources, but PSR J2021+4026, the first and only known gamma-ray variable pulsar, showed different spectral energy distributions, rotational light curves and spin frequencies before and after a significant gamma-ray flux jump. To discover more variable pulsars, we selected 35 variable gamma-ray pulsar candidates with radio glitches. We extracted the long-term light curves and performed detailed spectral and timing analysis on the 6-year data and data in different periods separated by glitches to look for variability related to glitches. Here, we present one of the candidates that shows different spectra before and after a glitch, while no significant corresponding variations in both photon flux and rotational light curve have been found.