AAS 199th meeting, Washington, DC, January 2002
Session 119. Magnetars and Pulsars

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[119.05] The High Resolution X-ray Spectrum of the Magnetic Pulsar PSR B0656+14

H.L. Marshall, N.S. Schulz (MIT CSR)

Observations of PSR B0656+14 using the Chandra Low Energy Transmission Grating Spectrometer are presented. The zeroth order events are pulsed at an amplitude of 10 +/- 2% and the image may be slightly extended. The extended emission is modelled as a Gaussian with a diameter of about 1.5", for a linear size (at a distance of 300 pc) of 6.5e15 cm. In the absence of systematic errors in the detector point spread function, the extended emission comprises < 50% of the observed flux in the 0.2-2.0 keV band, for a luminosity of < 1e32 erg/s. The spectrum is well modelled by a soft blackbody with T = 8.0 +/- 0.3 x 1e5 K with a size of 8.8 +/- 0.7 km in addition to a harder component that is modelled with either a power law or a higher temperature blackbody. Time-resolved spectroscopy shows that there is a weak absorption feature at 0.266 keV (observed frame) in the off-pulse spectrum, relative to the on-pulse spectrum. In a model where the the spectrum pulses at the 10% level in a spectrally independent way, the feature is marginally significant. This line has an equivalent width of 0.16 Angstroms and a width of 0.17 Angstroms in the time-averaged spectrum with a significance of 4.1 sigma relative to the continuum. This feature might be the first transition ever detected from atoms in strong magnetic and gravitational fields.


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