DISCOVERY OF X-RAY PULSATION FROM THE GEMINGA-LIKE PULSAR PSR J2021+4026

Abstract

We report the discovery of X-ray periodicity of ~265.3 ms from a deep\nXMM-Newton observation of the radio-quiet gamma-ray pulsar, PSR J2021+4026,\nlocated at the edge of the supernova remnant G78.2+2.1 (gamma-Cygni).The\ndetected frequency is consistent with the gamma-ray pulsation determined by the\nobservation of Fermi Gamma-ray Space Telescope at the same epoch. The X-ray\npulse profile resembles the modulation of hot spot on the surface of the\nneutron star. The phase-averaged spectral analysis also suggests that the\nmajority of the observed X-rays have a thermal origin. This is the third member\nin the class of radio-quiet pulsars with the significant pulsations detected\nfrom both X-rays and gamma-ray regimes.\n