Discovery of a GeV blazar shining through the Galactic plane

TL;DR

This paper reports the discovery and detailed multi-wavelength analysis of a new GeV blazar located through the Galactic plane, providing insights into its properties and confirming its classification as a flat-spectrum radio quasar.

Contribution

It presents the first comprehensive multi-wavelength characterization of a blazar seen through the Galactic plane, including redshift determination and spectral energy distribution analysis.

Findings

Redshift determined to be z=0.783

Classified as a flat-spectrum radio quasar

Confirmed blazar nature through spectral and variability analysis

Abstract

The \emph{Fermi} Large Area Telescope (LAT) discovered a new gamma-ray source near the Galactic plane, \object{Fermi J0109+6134}, when it flared brightly in 2010 February. The low Galactic latitude (b =-1.2\degr) indicated that the source could be located within the Galaxy, which motivated rapid multi-wavelength follow-up including radio, optical, and X-ray observations. We report the results of analyzing all 19 months of LAT data for the source, and of X-ray observations with both \emph{Swift} and the \emph{Chandra X-ray Observatory}. We determined the source redshift, z =0.783, using a Keck LRIS observation. Finally, we compiled a broadband spectral energy distribution (SED) from both historical and new observations contemporaneous with the 2010 February flare. The redshift, SED, optical line width, X-ray absorption, and multi-band variability indicate that this new GeV source is a blazar seen through the Galactic plane. Because several of the optical emission lines have equivalent width >5\AA, this blazar belongs in the flat-spectrum radio quasar category.