Phase Resolved Spectroscopy of PSR 0656+14
Abstract
We present results from phase resolved spectral analysis of PSR 0656+14, utilizing data from XMM-Newton. The light curve of PSR 0656+14 is found to be asymmetric and to vary as a function of energy, suggesting that the X-ray emission is comprised of multiple emission components. The X-ray spectrum is well fit by a three component model, consisting of two blackbody components plus a power law component. This model is interpreted as the combination of X-ray emission from surface cooling of a R(infinity) 7.5 ± 0.3 km neutron star with a temperature of 7.51 ± 0.21 x 105K, emission from a R(infinity) = 0.6 ± 0.1km radius hot polar cap at 1.64 ± 0.02 x 106 K, and low level power law emission from the pulsar magnetosphere, which is necessary to explain excess emission above 2.0 keV. Utilizing this model fit, the relative contributions of the spectral three components were fit as a function of phase. It was found that the emitting area of the hot polar cap varies sinusoidally. The surface cooling component temperature also varies approximately sinusoidally, 130 ± 10 degrees out of phase from the hot polar cap, suggesting an inhomogeneous temperature distribution on the neutron star surface. The power-law magnetospheric emission was not found to significantly vary as a function of phase. The combination of these two spectral components, varying with rotation phase, clearly explains the previously reported energy dependent, asymmetric nature of the PSR 0656+14 X-ray light curve.
- Publication:
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AAS/High Energy Astrophysics Division #8
- Pub Date:
- August 2004
- Bibcode:
- 2004HEAD....8.0821K