ar X iv : a st ro - p h / 96 01 16 7 v 1 2 9 Ja n 19 96 BATSE SD Observations of Hercules X - 1
نویسندگان
چکیده
The cyclotron line in the spectrum of the accretion-powered pulsar Her X-1 offers an opportunity to assess the ability of the BATSE Spectroscopy Detectors (SDs) to detect lines like those seen in some GRBs. Preliminary analysis of an initial SD pulsar mode observation of Her X-1 indicated a cyclotron line at an energy of ≈ 44 keV, rather than at the expected energy of ≈ 36 keV. Our analysis of four SD pulsar mode observations of Her X-1 made during high-states of its 35 day cycle confirms this result. We consider a number of phenomenological models for the continuum spectrum and the cyclotron line. This ensures that we use the simplest models that adequately describe the data, and that our results are robust. We find modest evidence (significance Q ∼ 10-10) for a line at ≈ 44 keV in the data of the first observation. Joint fits to the four observations provide stronger evidence (Q ∼ 10-10) for the line. Such a shift in the cyclotron line energy of an accretion-powered pulsar is unprecedented.
منابع مشابه
ar X iv : a st ro - p h / 96 01 12 9 v 1 2 3 Ja n 19 96 Is Her X - 1 a strange star
The possible identification of Her X-1 with a strange star (Li et al. 1995) is shown to be incorrect.
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