EDP Sciences
Free Access
Volume 438, Number 1, July IV 2005
Page(s) 211 - 218
Section Stellar structure and evolution
DOI https://doi.org/10.1051/0004-6361:20042470
Published online 06 July 2005

A&A 438, 211-218 (2005)
DOI: 10.1051/0004-6361:20042470

Discovery of 1323 s pulsations from RX J0103.6-7201: The longest period X-ray pulsar in the SMC

F. Haberl and W. Pietsch

Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
    e-mail: fwh@mpe.mpg.de

(Received 2 December 2004 / Accepted 16 March 2005 )

XMM-Newton archival observations of the Be/X-ray binary candidate revealed pulsations with a period of ~1323 s. This makes the X-ray pulsar with the longest period known in the Small Magellanic Cloud (SMC). More than 150 X-ray observations of by ROSAT, Chandra and XMM-Newton show flux variations by a factor of 50 on time scales of days to years. Using the accurate positions obtained from ACIS-I images, the optical counterpart is identified as a V = 14.6 mag emission line star. EPIC spectra of above 1 keV are consistent with an absorbed power-law with column density between (6-9) $\times$ 1021 cm-2, except during one observation when an extraordinary high value of 1.1 $\times$ 1023 cm-2 was measured which strongly attenuated the power-law emission below 3 keV. A soft excess between 0.5 and 1.0 keV is evident in the spectra which becomes best visible in the highly absorbed spectrum. The soft component can be reproduced by a thermal plasma emission model with its luminosity strongly correlated with the total intrinsic source luminosity. Including results from three other SMC Be/X-ray binaries extends the linear correlation over three orders of magnitude in source intensity, strongly suggesting that the same mechanism is responsible for the generation of the soft emission.

Key words: galaxies: individual: small Magellanic Cloud -- stars: neutron -- X-rays: binaries -- X-rays: galaxies -- X-rays: individual: -- stars: emission-line, Be

SIMBAD Objects

© ESO 2005

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.