Identification of blazar candidates behind Small and Large Magellanic Clouds

TL;DR

This paper identifies 44 blazar candidates behind the Magellanic Clouds using multi-wavelength data, providing a valuable sample for studying blazar physics, magnetic fields, and gamma-ray detection prospects.

Contribution

The study presents the first systematic identification of blazar candidates behind the Magellanic Clouds using radio, optical, and infrared data, expanding the catalog of such objects in this region.

Findings

44 blazar candidates identified, including 27 flat spectrum radio quasars and 17 BL Lac objects.

Candidates characterized by multi-wavelength data, including radio polarization for nine objects.

Potential for these objects to be used in studies of blazar variability, magnetic fields, and gamma-ray observations.

Abstract

We report the identification of blazar candidates behind the Magellanic Clouds. The objects were selected from the Magellanic Quasars Survey (MQS), which targeted the entire Large Magellanic Cloud (LMC) and 70\% of the Small Magellanic Cloud (SMC). Among the 758 MQS quasars and 898 of unidentified (featureless spectra) objects, we identified a sample of 44 blazar candidates, including 27 flat spectrum radio quasars and 17 BL Lacertae objects, respectively. All the blazar candidates from our sample were identified with respect to their radio, optical, and mid-infrared properties. The newly selected blazar candidates possess the long-term, multi-colour photometric data from the Optical Gravitational Lensing Experiment, multi-colour mid-infrared observations, and archival radio data for one frequency at least. In addition, for nine of them the radio polarization data are available. With such data, these objects can be used to study the physics behind the blazar variability detected in the optical and mid-infrared bands, as a tool to investigate magnetic field geometry of the LMC and SMC, and as an exemplary sample of point like sources most likely detectable in $\gamma$-ray range with the newly emerging Cherenkov Telescope Array.