Discovery of X-ray pulsations from the next Geminga, PSR J1836+5925

Abstract

We report recent XMM-Newton investigations of PSR J1836+5925, the "next Geminga," which determined an X-ray pulsation of ∼173.3 ms. Its X-ray periodicity is consistent with the γ-ray ephemeris at the same epoch. The X-ray folded light curve has a sinusoidal structure that is different from the double-peaked γ-ray pulse profile. We have also analyzed the X-ray phase-averaged spectra which shows that the X-ray emission from PSR J1836+5925 is thermal dominant. This suggests that the X-ray pulsation mainly originates from the modulated hot spot on the stellar surface.