Soft X-ray imaging observations of the 39 millisecond pulsar PSR 1951+32.

Abstract

The authors report observations of the newly discovered 39.5 millisecond pulsar PSR 1951+32 with the soft X-ray telescope on board the EXOSAT observatory. A point-like source coincident with the position of the pulsar was observed. For a power-law model with photon index of -2, a column density of 6×10²¹cm^-2, and a distance of 2.5 kpc, the observed count rate corresponds to a luminosity of 1.5×10³⁴erg s^-1 in the energy range 0.03 - 2.4 keV. For a blackbody model, surface temperatures in the range (1.1 - 2.1)×10⁶K would be required to account for the observed count rate. The observed events from the source were searched at the extrapolated radio period for pulsations. A weak signal at 97% confidence level was found, indicating that the X-ray flux from PSR 1951+32 can be all pulsed.