RXTE and XMM observations of intermediate polar candidates

¹ Department of Physics and AstronomyUniversity of Leicester, Leicester, LE1 7RH, UK
e-mail: oliver.butters@star.le.ac.uk
² Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
³ CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771, USA
⁴ Department of Physics, University of Maryland, Baltimore county, 1000 Hilltop Circle, Baltimore, MD 21250, USA
⁵ Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450, USA

Received: 30 September 2010
Accepted: 21 November 2010

Abstract

Aims. We aim to determine the credentials of nine candidate intermediate polars in order to confirm whether or not they are magnetic cataclysmic variables.

Methods. Frequency analysis of RXTE and XMM data was used to search for temporal variations that could be associated with the spin period of the magnetic white dwarf. X-ray spectral analysis was carried out to characterize the emission and absorption properties of each target.

Results. The hard X-ray light curve of V2069 Cyg shows a pulse period of 743.2 s, and its spectrum is fit by an absorbed bremsstrahlung model with an iron line, confirming this to be a genuine intermediate polar. The hard X-ray light curve of the previously confirmed intermediate polar IGR J00234+6141 is shown to be consistent with the previous low-energy X-ray detection of a 563.5 s pulse period. The likely polar IGR J14536–5522 shows no coherent modulation at the previously identified period of 3.1 h, but does exhibit a clear signal at periods likely to be harmonically related to it. Whilst our RXTE observations of RX J0153.3+7447, Swift J061223.0+701243.9, V436 Car, and DD Cir are largely too faint to give any definitive results, the observations of IGR J16167–4957 and V2487 Oph show some characteristics of intermediate polars, and these objects remain good candidates.

Conclusions. We confirmed one new hard X-ray selected intermediate polar from our sample, V2069 Cyg.