Two new high energy gamma-ray blazar candidates

TL;DR

This paper reports the discovery of two new high-energy gamma-ray blazar candidates detected by Fermi-LAT, with multi-wavelength analysis suggesting their blazar nature despite one having an unusual optical spectrum.

Contribution

The study introduces two new gamma-ray sources as blazar candidates, including one newly discovered source and analysis of their multi-wavelength properties and spectra.

Findings

One source is a new gamma-ray discovery at high Galactic latitude.

Both sources exhibit infrared colors typical of blazars.

One source has an optical spectrum resembling a white dwarf star.

Abstract

We report the detection of two new gamma-ray sources in the Fermi-LAT sky (Pass 8) at energies higher than 20 GeV, and confirmed at lower energies, using a source detection tool based on the Minimum Spanning Tree algorithm. One of these sources, at a Galactic latitude of about -4{\deg}, is a new discovery, while the other was previously reported above 50 GeV in the 2FHL catalogue. We searched for archival multi-wavelength data of possible counterparts and found interesting candidates. Both objects are radio sources and their WISE infrared colours are typical of blazars. While for the former source no optical spectra are available, for the latter a puzzling optical spectrum corresponding to a white dwarf star is found in the 6dF database. We discuss the spectral energy distributions of both sources and possible interpretations.