Letter to the Editor
RXTE confirmation of the intermediate polar status of Swift J0732.5–1331
Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK e-mail: email@example.com
2 CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771, USA; Department of Physics, University of Maryland, Baltimore county, 1000 Hilltop Circle, Baltimore, MD 21250, USA
Accepted: 18 September 2007
Aims.We intend to establish the X-ray properties of Swift J0732.5–1331 and therefore confirm its status as an intermediate polar.
Methods.We analysed 36 240 s of X-ray data from RXTE. Frequency analysis was used to constrain temporal variations and spectral analysis used to characterise the emission and absorption properties.
Results.The X-ray spin period is confirmed to be 512.4(3) s with a strong first harmonic. No modulation is detected at the candidate orbital period of 5.6 h, but a coherent modulation is present at the candidate 11.3 h period. The spectrum is consistent with a 37 keV bremsstrahlung continuum with an iron line at 6.4 keV absorbed by an equivalent hydrogen column density of around 1022 atoms cm-2.
Conclusions.Swift J0732–1331 is confirmed to be an intermediate polar.
Key words: stars: binaries: general / stars: novae, cataclysmic variables / stars: individual: Swift J0732.5–1331 / X-rays: binaries
© ESO, 2007