Swift-XRT follow-up analysis of unidentified hard X-ray sources
arXiv:2408.05303 · doi:10.1051/0004-6361/202348401
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.
21 pages, 5 tables, 13 figures, accepted for publication in A&A - pre-proofs version, catalog tables will be available online
References in corpus (26)
- The 1% Concordance Hubble Constant
- BAT AGN Spectroscopic Survey I: Spectral Measurements, Derived Quantities, and AGN Demographics
- Swift BAT Survey of AGN
- INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth
- INTEGRAL/IBIS all-sky survey in hard X-rays
- BASS XXII: The BASS DR2 AGN Catalog and Data
- Unveiling the nature of INTEGRAL objects through optical spectroscopy. V. Identification and properties of 21 southern hard X-ray sources
- X-ray spectral evolution of TeV BL Lac objects: eleven years of observations with BeppoSAX, XMM-Newton and SWIFT satellites
- The WISE Blazar-Like Radio-Loud Sources: An All-Sky Catalog Of Candidate Gamma-Ray Blazars
- Unveiling the nature of INTEGRAL objects through optical spectroscopy. VI. A multi-observatory identification campaign
- Two new catalogs of blazar candidates in the WISE infrared sky
- Unveiling the nature of the unidentified gamma-ray sources IV: the catalog of potential X-ray counterparts
- INTEGRAL/IBIS 17-yr hard X-ray all-sky survey
- BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGN
- The Infrared-Gamma-Ray Connection: A WISE View of the Extragalactic Gamma-Ray Sky
- The deep look onto the hard X-ray sky: The Swift - INTEGRAL X-ray (SIX) survey
- Optical spectroscopic observations of low-energy counterparts of Fermi-LAT gamma-ray sources
- INTEGRAL 11-year hard X-ray survey above 100 keV
- The -ray sky seen at X-ray energies I. Searching for the connection between X-rays and -rays in Fermi BL Lac objects
- 15 years of Galactic surveys and hard X-ray Background measurements
- The -ray sky seen at X-ray energies II: the Swift hunt of Fermi BL Lac objects among unidentified gamma-ray sources
- Chandra Observations of High Energy X-ray Sources Discovered by INTEGRAL
- Powerful Radio Sources in the Southern Sky. I. Optical Identifications
- Optical spectroscopic classification of 35 hard X-ray sources from the Swift-BAT 70-month catalogue
- Powerful Radio Sources in the Southern Sky. II. A SWIFT X-Ray Perspective
- A multifrequency characterization of the extragalactic hard X-ray sky