Using X-ray catalogues to find counterparts to unassociated high-energy Fermi/LAT sources

TL;DR

This paper investigates unassociated high-energy Fermi/LAT sources using X-ray catalogues, focusing on nine blazar counterparts, revealing their optical classifications and redshift information.

Contribution

It provides a preliminary analysis linking unassociated Fermi sources to optical blazar counterparts using X-ray data, a novel approach for this source class.

Findings

All nine sources are blazars, eight BL Lac and one FSRQ.

Most sources are at redshift greater than 0.1.

The study successfully identified optical counterparts for these high-energy sources.

Abstract

The first Fermi Large Area Telescope (LAT) catalogue of sources (1FHL) emitting at high energies (above 10 GeV) reports the details of 514 objects detected in the first three years of the Fermi mission. Of these, 71 were reported as unidentified in the 1FHL catalogue, although six are likely to be associated with a supernova remnant (SNR), a Pulsar Wind Nebula (PWN) or a combination of both, thereby leaving a list of 65 still unassociated objects. Herein, we report a preliminary analysis on this sample of objects concentrating on nine 1FHL sources, which were found to have a clear optical extragalactic classification. They are all blazar, eight BL Lac and one flat spectrum radio quasar, typically at redshift greater than 0.1.