Letter to the Editor
Discovery of the INTEGRAL X/γ-ray transient IGR J00291+5934: A Comptonised accreting ms pulsar?
School of Physics and Astronomy, University of Southampton, SO17 1BJ, UK
2 Science Data Centre, 1290 Versoix, Switzerland e-mail: email@example.com
3 Observatoire de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
4 CEA Saclay, DSM/DAPNIA/SAp (CNRS FRE 2591), 91191 Gif-sur-Yvette Cedex, France
5 Istituto di Astrofisica Spaziale, CNR/INAF, via Fosso del Cavaliere 100, 00133 Rome, Italy
6 NASA Goddard Space Flight Center, Code 661, Building 2, Greenbelt, MD 20771, USA
Accepted: 23 January 2005
We report the discovery of a high-energy transient with the IBIS/ISGRI detector on board the INTEGRAL observatory. The source, namely IGR J00291+5934, was first detected on 2nd December 2004 in the routine monitoring of the IBIS/ISGRI 20-60 keV images. The observations were conducted during Galactic Plane Scans, which are a key part of the INTEGRAL Core Programme observations. After verifying the basic source behaviour, the discovery was announced on 3rd December. The transient shows a hard Comptonised spectrum, with peak energy release at about 20 keV and a total luminosity of ~ erg s-1 in the 5-100 keV range, assuming a distance of 3 kpc. Following the INTEGRAL announcement of the discovery of IGR J00291+5934, a number of observations were made by other instruments. We summarise the results of those observations and, together with the INTEGRAL data, identifiy IGR J00291+5934 as the 6th member of a class of accreting X-ray millisecond pulsars.
Key words: gamma-rays: observations / pulsars: individual IGR J00291+5934
© ESO, 2005