Discovery of X-ray Pulsation from the Geminga-like Pulsar PSR J2021+4026

TL;DR

This paper reports the discovery of X-ray pulsations at approximately 265.3 ms from the radio-quiet gamma-ray pulsar PSR J2021+4026, confirming its pulsar nature and thermal X-ray emission.

Contribution

The study presents the first detection of X-ray pulsations from PSR J2021+4026, linking X-ray and gamma-ray emissions in this radio-quiet pulsar.

Findings

X-ray pulsation period of ~265.3 ms detected

X-ray pulse profile resembles hot spot modulation

X-ray emission is primarily thermal in origin

Abstract

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