Multiwavelength properties of a new Geminga-like pulsar: PSR J2021+4026

In this paper, we report a detailed investigation of the multiwavelength properties of a newly detected γ−ray pulsar, PSR J2021+4026, in both observational and the-oretical aspects. We firstly identify an X-ray source in the XMM-Newton serendipi-tous source catalogue, 2XMM J202131.0+402645, located within the 95 % confidence circle of PSR J2021+4026. With an archival Chandra observation, this identifica-tion provides an X-ray position with arcsecond accuracy which is helpful in facilitat-ing further investigations. Searching for the pulsed radio emission at the position of 2XMM J202131.0+402645 with a 25-m telescope at Urumqi Astronomical Observa-tory resulted in null detection and places an upper-limit of 0.1 mJy for any pulsed signal at 18 cm. Together with the emission properties in X-ray and γ−ray, the radio quietness suggests PSR J2021+4026 to be another member of Geminga-like pulsars. In the radio sky survey data, extended emission features have been identified in the γ−ray error circle of PSR J2021+4026. We have also re-analyzed the γ−ray data collected by FERMI ’s Large Area Telescope. We found that the X-ray position of 2XMM J202131.0+402645 is consistent with that of the optimal γ − ray timing so-lution. We have further modeled the results in the context of outer gap model which provides us with constraints for the pulsar emission geometry such as magnetic incli-nation angle and the viewing angle. We have also discussed the possibility of whether PSR J2021+4026 has any physical association with the supernova remnant G78.2+2.1 (γ−Cygni)