EDP Sciences
Free access
Volume 434, Number 3, May II 2005
Page(s) 1097 - 1105
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20040368

A&A 434, 1097-1105 (2005)
DOI: 10.1051/0004-6361:20040368

PSR B1929+10 revisited in X-rays

A. Slowikowska1, L. Kuiper2 and W. Hermsen2

1  Nicolaus Copernicus Astronomical Center, Rabianska 8, 87-100 Torun, 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)

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 Pulsed emission was detected at a more than five sigma level for the combined ROSAT PSPC-B and previously unpublished HRI data.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 $0.25 \pm 0.04$. The pulsed signal has also been detected in the ASCA GIS data (0.5-5 keV) with a similar pulsed fraction of $0.36 \pm 0.11$. No significant timing signal is found in the RXTE PCA data (> 2 keV). 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 $\alpha$ of $2.54 \pm 0.12$ and a neutral hydrogen column density $N_{\hbox {\scriptsize\rm H}}$ towards the source of $9.8_{-1.0}^{+1.4} \times 10^{20}\
\mathrm{cm^{-2}}$. For a double black-body fit our results are $T_\mathrm{1} =
2.0_{-0.05}^{+0.05} \times 10^{6}~\mathrm{K}$, $T_\mathrm{2} =
6.9_{-0.35}^{+0.23} \times 10^{6}\ \mathrm{K}$ and $N_{\hbox {\scriptsize\rm H}}$  $ = 4.4_{-1.1}^{+2.1}
\times 10^{20}\ \mathrm{cm^{-2}}$. In both cases the derived value of $N_{\hbox {\scriptsize\rm H}}$ is higher than that adopted in earlier works, but our result is fully consistent with the larger distance estimate of $331 \pm 10\ \mathrm{pc}$ from parallax measurements combined with the hydrogen distribution measurements in the direction to the pulsar.

Key words: stars: neutron -- pulsars: individual: PSR B1929+10

SIMBAD Objects

© ESO 2005