GMRT observations of the field of INTEGRAL X-ray sources. II

¹ Department of Physics, Mumbai University, Mumbai, 400 098, India e-mail: mamta@ncra.tifr.res.in
² NCRA, TIFR, Post Bag 3, Ganeshkhind, Pune, 411 007, India
³ Department of Astronomy and Astrophysics, TIFR, Colaba, Mumbai, 400005, India
⁴ CNRS FRE 2591/CEA Saclay, DSM/DAPNIA/SAP, 91191 Gif-sur-Yvette Cedex, France

Received: 28 September 2005
Accepted: 8 February 2006

Abstract

We conducted low-frequency radio observations with the Giant Metrewave Radio Telescope (GMRT) of the 40 new hard X-ray sources discovered by the INTEGRAL satellite. This survey was conducted in order to study radio emissions from these sources, to provide precise position, and to identify new microquasar candidates. Our observations show that 24 of the X-ray sources have radio candidates within the INTEGRAL error circle. Based on the radio morphology, variability, and information available from different wavelengths, we categorize them as seventeen Galactic sources (4 unresolved, 7 extended, 6 extended sources in diffuse regions) and seven extragalactic sources (2 unresolved, 5 extended). A detailed account of seventeen of these sources was presented in an earlier paper. Based on the radio data for the remaining sources at 0.61 GHz and on the available information from NVSS, DSS, 2MASS, and NED, we have identified possible radio counterparts for the hard X-ray sources. The three unresolved sources, i.e., IGR J17303-0601, IGR J17464-3213, and IGR J18406-0539, are discussed in detail. These sources have been associated with compact sources that are variable in radio and X-rays. The remaining fourteen sources have an extended radio morphology and either are diffuse Galactic regions or have an extragalactic origin.