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Astron. Astrophys. 323, 839-843 (1997)


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Photometry and proper motion of the Vela pulsar *

F.P. Nasuti 1, R. Mignani 1, P.A. Caraveo 1 and G.F. Bignami 1, 2

1 Istituto di Fisica Cosmica del CNR, Via Bassini 15, I-20133 Milano, Italy
2 Dipartimento di Ingegneria Industriale, Universitá di Cassino, I-03043 Cassino, Italy

Received 27 June 1996 / Accepted 29 August 1996

Abstract

We present the first UBVR photometry of the Vela Pulsar. All observed colours lie significantly above any Rayleigh-Jeans extrapolation of the ROSAT soft X-ray black body curve. While the U, B and V fluxes can be described by a flat power law, the R point lies about 1 magnitude below the expectation. An evidence for a similar spectral turnover, but at longer wavelength, was also claimed for the Crab Pulsar, another young INS with non-thermal optical emission. However, to account for the Vela R point in term of synchrotron self absorption, the emission geometry of the two pulsars must be different.

In parallel, we have used the new images to re-assess the proper motion of the Vela pulsar, an effect for which vastly different results have been reported in the literature.

Key words: pulsars: Vela pulsar – astrometry

* Based on observations collected at the European Southern Observatory, La Silla, Chile.

Send offprint requests to: P. Caraveo

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998

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