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Register a new userDiscovery of X-ray pulsations from next Geminga - PSR J1836+5925
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Added by
Chung Yue Hui David
Publication date
2014
fields
Physics
and research's language is
English
Authors
L. C. C. Lin
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We report the X-ray pulsation of ~173.3 ms for the next Geminga, PSR J1836+5925, with recent XMM-Newton investigations. The X-ray periodicity is consistent wtih the gamma-ray ephemeris at the same epoch. The X-ray folded light curve has a sinusoidal structure which is different from the double-peaked gamma-ray pulse profile. We have also analysed the X-ray phase-averaged spectra which shows the X-ray emission from PSR J1836+5925 is thermal dominant. This suggests the X-ray pulsation mainly originates from the modulated hot spot on the stellar surface.
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We report the discovery of soft X-ray pulsations from the nearby millisecond pulsar PSR J1231$-$1411 using NICER. The pulsed emission is characterized by a broad and asymmetric main pulse and a much fainter secondary interpulse, with a total pulsed count rate of 0.055 c s$^{-1}$ in the 0.35-1.5 keV band. We analyzed Fermi LAT data to update the pulse timing model covering 10 years of data and used that model to coherently combine NICER data over a year of observations. Spectral modeling suggests that the flux is dominated by thermal emission from a hot spot (or spots) on the neutron star surface. The phase relationship between the X-ray pulse and the radio and $gamma$ rays provides insight into the geometry of the system.
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