Optical and X-ray observations of IGR J00291+5934 in quiescence
Jonker, P. G., Torres, M. A. P. and Steeghs, D.. (2008) Optical and X-ray observations of IGR J00291+5934 in quiescence. Astrophysical Journal, Vol.680 (No.1). pp. 615-619. ISSN 0004-637XFull text not available from this repository.
Official URL: http://dx.doi.org/10.1086/587617
We report on optical and X-ray observations of the accretion-powered millisecond pulsar IGR J00291+5934 in quiescence. Time-resolved I-band photometry has been obtained with the 4.2 m William Herschel Telescope, while a 3 ks Chandra observation provided contemporaneous X-ray coverage. We found an unabsorbed 0.5-10 keV X-ray flux of 1 x 10(-13) erg cm(-2) s(-1), which implies that the source was in quiescence at the time of the optical observations. Nevertheless, the optical I-band light curve of IGR J00291+5934 shows evidence for strong flaring. After removal of the strongest flares, we find evidence for an orbital modulation in the phase-folded I-band light curve. The overall modulation can be described by effects resulting from the presence of a superhump. Comparing our light curve with that reported recently we find evidence for a change in the quiescent base level. Similar changes have now been reported for four soft X-ray transients, implying that they may be a common feature of such systems in quiescence. Furthermore, the maximum in our folded light curve occurs at a different phase than observed before.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Astrophysical Journal|
|Official Date:||10 June 2008|
|Number of Pages:||5|
|Page Range:||pp. 615-619|
|Access rights to Published version:||Restricted or Subscription Access|
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