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Discovery of a 7 Second Anomalous X-ray Pulsar in the Distant Milky Way

E. V. Gotthelf·G. Vasisht
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Abstract

We report the serendipitous discovery of a 7-s X-ray pulsar using data acquired with the Advanced Satellite for Cosmology and Astrophysics. The pulsar is detected as an unresolved source located towards a region of the Galactic plane (l,b ~ 29.5, 0.08) that coincides with an overdensity of star-formation tracers. The signal suffers tremendous foreground absorption, equivalent to N_H ~ 10E23 cm^-2; the absorption correlates well with a line-of-sight that is tangential to the inner spiral arms and the 4-kpc molecular ring. The pulsar is not associated with any known supernova remnants or other cataloged objects in that direction. The near sinusoidal pulse (period P ~ 6.9712) is modulated at 35% pulsed amplitude, and the steep spectrum is characteristic of hot black-body emission with temperature kT ~ 0.65 keV. We characterize the source as an anomalous X-ray pulsar (AXP).

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E. V. Gotthelf, G. Vasisht. 1998-04-02. Discovery of a 7 Second Anomalous X-ray Pulsar in the Distant Milky Way. https://doi.org/10.1016/s1384-1076(98)00014-1

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