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arXiv · 2408.05303

Swift-XRT follow-up analysis of unidentified hard X-ray sources

M. Kosiba·F. Massaro·A. Paggi·H. A. Peña-Herazo·N. Masetti·V. Chavushyan·E. Bottacini·N. Werner
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Abstract

It is currently established that the sources contributing to the cosmic X-ray background (CXB) emission are mainly nearby active galactic nuclei (AGN), in particular those that are obscured. Thus, it is important to fully identify the hard X-ray sky source population to accurately characterize the individual contribution of different AGNs to the overall CXB emission. We present a follow-up analysis of all the 218 sources marked as unidentified in our previous revision of the third release of the Palermo Swift-BAT hard X-ray catalog (3PBC) based on our multifrequency classification scheme. These 218 sources were classified as unidentified in our previous analyses because they lack an assigned low-energy counterpart. We searched for soft X-ray counterparts of these 218 3PBC sources in archival Swift-XRT observations obtained between 2005 January 1st and 2018 August 1st. In particular, we found 1213 archival Swift-XRT observations for 192 of the 218 unidentified sources. We found 93 possible Swift-XRT counterparts inside of the Swift-BAT positional uncertainty regions. These correspond to 73 3PBC sources, where 60 have only a single Swift-XRT detection, and 13 sources have multiple detections. We present a catalog of all the detected possible counterparts of the yet unidentified hard X-ray sources to the community as a catalog for future spectroscopic follow-up targets, together with a short catalog of our classification of the ten sources for which we found available spectra.

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M. Kosiba, F. Massaro, A. Paggi, H. A. Peña-Herazo, N. Masetti, V. Chavushyan, E. Bottacini, N. Werner. 2024-08-09. Swift-XRT follow-up analysis of unidentified hard X-ray sources. https://doi.org/10.1051/0004-6361%2F202348401

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