The AGN nature of three INTEGRAL sources: IGR J18249-3243, IGR J19443+2117, and IGR J22292+6647

Context: The third INTEGRAL/IBIS survey has revealed several new hard X-ray sources, which are still unidentified or unclassified. To identify these sources, we need to find their counterparts at other wavelengths and then study their nature.
Aims: The aim of this work is to employ the capability of the X-ray telescope (XRT) onboard Swift to localise the sources with a positional accuracy of few arcseconds, thus allowing the search for optical/UV, infrared, and radio counterparts to be more efficient and reliable. A second objective is to provide spectral information over a broad range of frequencies.
Methods: We analysed all XRT observations available for three unidentified INTEGRAL sources, IGR J18249-3243, IGR J19443+2117, and IGR J22292+6647, localised their soft X-ray counterparts, and searched for associations with objects in the radio band. We also combined X-/gamma-ray data, as well as all the available radio, infrared, and optical/UV information, in order to provide a broad-band spectral characterisation of each source and investigate its nature.
Results: In all three cases, XRT observations provided a firm localisation of the X-ray counterpart and information on its optical/UV, infrared, and radio associations. All three sources are found to be bright and repeatedly observed radio objects, although poorly studied. The X-/gamma-ray spectrum of each source is described well by power laws with the photon indices typical of AGN; however, only IGR J19443+2117 may have absorption in excess of the Galactic value, while IGR J22292+6647 is certainly variable at X-ray energies. IGR J18249-3243 has a complex radio morphology and a steep radio spectrum, while the other two sources show flatter radio spectra and a more compact morphology. Overall, their radio, optical/UV, and infrared characteristics, as well as their X-/gamma-ray properties, point to an AGN classification for all three objects.

Partly based on observations collected at the Astronomical Observatory of Bologna in Loiano (Italy).