EDP Sciences
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Volume 374, Number 2, August I 2001
Page(s) 584 - 587
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20010781

A&A 374, 584-587 (2001)
DOI: 10.1051/0004-6361:20010781

Spectroscopy of the Crab Pulsar

G. M. Beskin1, 2 and V. V. Neustroev1, 3

1  Special Astrophysical Observatory, Nizhnij Arkhyz, Karachaevo-Cherkesia, 369167, Russia
2  Isaac Newton Institute of Chile, SAO Branch, Chile
3  Department of Astronomy and Mechanics, Udmurt State University, 1, Universitetskaia, Izhevsk, 426034, Russia
    e-mail: benj@uni.udm.ru

(Received 5 April 2001 / Accepted 7 May 2001)

We present new, high signal-to-noise spectroscopy of the Crab Pulsar in the range $\lambda \lambda 5000{-}7000$ Å. The observations were carried out with the 6-meter telescope of the SAO with the spectrograph SP-124 with a resolution of 2 Å. After reduction of the Crab Nebula emission, the dereddened pulsar spectrum can be fitted by a power law with $\alpha = -0.15\pm 0.15$. There are no lines (emission and absorption) with a relative intensity (depth) of more than 2% (with a confidential probability of 99% ). At this level we did not find absorption at $\lambda 6000$ Å, possibly of ion-cyclotron origin, as detected by Nasuti et al. (1996). This detail can be variable as a consequence of the variability of the ion ejection from the neutron star (NS) surface. We suggest a possible relationship between ejection intensity and inhomogeneity of the NS surface connected with pulsar glitches.

Key words: stars: pulsars: individual (Crab Pulsar); pulsars: general -- stars: neutron

Offprint request: G. Beskin, beskin@sao.ru

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