The optical counterpart of IGR J00291+5934 in quiescence

• Published in: Astronomy and astrophysics (Berlin) 2007-09, Vol.472 (3), p.881-885
• Main Authors: D'Avanzo, P., Campana, S., Covino, S., Israel, G. L., Stella, L., Andreuzzi, G.
• Format: Article
• Language: English
• Subjects: accretion; accretion disks; Astronomy; Earth, ocean, space; Exact sciences and technology; stars: neutron; X-rays: binaries
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20077395

Aims.The recent (December 2004) discovery of the sixth accretion-powered millisecond X-ray pulsar IGR J00291+5934 provides a very good chance to deepen our knowledge of such systems. Although these systems are well studied at high energies, poor informations are available for their optical/NIR counterparts during quiescence. Up to now, only for SAX J1808.4-3658, the first discovered system of this type, we have a secure multiband detection of its optical counterpart in quiescence. Among the seven known system IGR J00291+5934 is the one that resembles SAX J1808.4-3658 more closely. Methods.With the Italian 3.6 m TNG telescope, we have performed deep optical and NIR photometry of the field of IGR J00291+5934 during quiescence in order to look for the presence of a variable counterpart. Results.We present here the first multiband (VRIJH) detection of the optical and NIR counterpart of IGR J00291+5934 in quiescence as well as a deep upper limit in the K-band. We obtain an optical light curve that shows variability consistent with a sinusoidal modulation at the known 2.46 h orbital period and present evidence for a strongly irradiated companion.