PSR B1929+10 revisited in X-rays

¹ Nicolaus Copernicus Astronomical Center, Rabiańska 8, 87-100 Toruń, Poland e-mail: aga@ncac.torun.pl
² SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: [L.M.Kuiper;W.Hermsen]@sron.nl

Received: 2 March 2004
Accepted: 3 January 2005

Abstract

We performed timing and spectral analyses for PSR B1929+10, one of the oldest (~10⁷ years) of the ordinary pulsars detected in X-rays, using archival ROSAT, ASCA and RXTE data. Pulsed emission was detected at a more than five sigma level for the combined ROSAT PSPC-B and previously unpublished HRI data. Our pulse profile is in agreement with that obtained by Yancopoulos et al. (1994, ApJ, 429, 832, ROSAT PSPC-B) but now with better statistics. The pulsed fraction in the ROSAT X-ray band is . The pulsed signal has also been detected in the ASCA GIS data (0.5–5 keV) with a similar pulsed fraction of . No significant timing signal is found in the RXTE PCA data . We found that the combined ROSAT PSPC-B and ASCA GIS spectrum can satisfactorily be described by a power-law as well as by a double black-body model but not by a single black-body model or black-body plus power law model. Fitting the combined ROSAT/ASCA 0.1–10 keV spectrum by a power-law model we obtain a photon index α of and a neutral hydrogen column density  towards the source of . For a double black-body fit our results are , and . In both cases the derived value of is higher than that adopted in earlier works, but our result is fully consistent with the larger distance estimate of from parallax measurements combined with the hydrogen distribution measurements in the direction to the pulsar.