The Gamma-ray Blazar Quest: new optical spectra, state of art and future perspectives

TL;DR

This paper presents a method to identify gamma-ray blazar candidates using infrared colors, confirms their nature through optical spectroscopy, and discusses current and future efforts to discover new gamma-ray blazars.

Contribution

It introduces an improved procedure combining infrared color analysis with optical spectroscopy to confirm gamma-ray blazar candidates and updates the archival search with SDSS data.

Findings

Identification of new gamma-ray blazar candidates.

Confirmation of candidate nature through optical spectra.

Enhanced methodology for blazar discovery.

Abstract

We recently developed a procedure to recognize gamma-ray blazar candidates within the positional uncertainty regions of the unidentified/unassociated gamma-ray sources (UGSs). Such procedure was based on the discovery that Fermi blazars show peculiar infrared colors. However, to confirm the real nature of the selected candidates, optical spectroscopic data are necessary. Thus, we performed an extensive archival search for spectra available in the literature in parallel with an optical spectroscopic campaign aimed to reveal and confirm the nature of the selected gamma-ray blazar candidates. Here, we first search for optical spectra of a selected sample of gamma-ray blazar candidates that can be potential counterparts of UGSs using the Sloan Digital Sky Survey (SDSS DR12). This search enables us to update the archival search carried out to date. We also describe the state-of-art and the future perspectives of our campaign to discover previously unknown gamma-ray blazars.