The populations of hard X- and {\gamma}-ray sources: a correlation study and new possible identifications

TL;DR

This study cross-correlates Fermi-LAT gamma-ray sources with Swift-BAT hard X-ray sources, identifying common sources, assessing their nature, and supporting some as blazars through spectral analysis and population comparison.

Contribution

It provides a new combined catalog of sources emitting in both hard X-ray and gamma-ray bands, with detailed analysis of their properties and classifications.

Findings

Identified a sample of sources emitting in both energy bands.

Supported classification of two sources as blazars.

Compared blazar populations in gamma-ray and X-ray catalogs.

Abstract

We present the results of our analysis devoted to the research of sources emitting in the energy bands surveyed by both the Swift-BAT and the Fermi-LAT telescopes. We cross-correlate the Fermi-LAT 1-year point source catalogue (1FGL) of {\gamma}-ray sources and the second Palermo BAT catalogue (2PBC) of hard X-ray sources, establishing a correspondence between sources when their error boxes overlap. We also extract the significance value in the BAT 15-150 keV map, obtained using a dedicated software for the reduction of BAT data, in the direction of the 1FGL sources and take into account those above the significance threshold {\sigma} = 3. We obtain a sample of common sources emitting in both the hard X- and the {\gamma}-ray energy bands and evaluate its content in galactic and extragalactic objects. We assess the fraction of unidentified sources and describe in greater detail the properties of two of them, 1FGL J0137.8+5814 and 1FGL J2056.7+4938, supporting their classification as blazars after the analysis of their broad-band spectral energy distribution. We discuss the blazar content of the collected 1FGL-2PBC sources: we build its redshift distibution and compare it with that of the whole blazar population as reported in the second edition of the BZCAT blazar catalogue.