Two new high energy gamma-ray blazar candidates

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°, 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.

7 pages, 6 figures. Accepted for publication in MNRAS

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• High energy gamma-ray detection of supernova remnants in the Large Magellanic Cloud
• Search for $\gamma$-ray emission from SNRs in the Large Magellanic Cloud: a new cluster analysis at energies above 4 GeV
• New blazar candidates from the 9Y-MST catalogue detected at energies higher than 10 GeV