Discovery of A GeV Blazar Shining Through the Galactic Plane

Vandenbroucke, J.
Buehler, R.
Ajello, M.
Bechtol, K.
Bellini, A.
Bolte, M.
Cheung, C. C.
Civano, F.
Donato, D.
Fuhrmann, L.
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The Fermi Large Area Telescope (LAT) discovered a new gamma-ray source near the Galactic plane, Fermi J0109+6134, when it flared brightly in 2010 February. The low Galactic latitude (b = -1 degrees.2) 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 Swift and the Chandra X-ray Observatory. We determined the source redshift, z = 0.783, using a Keck Low-Resolution Imaging Spectrometer 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 angstrom, this blazar belongs in the flat-spectrum radio quasar category.

Vandenbroucke, J., R. Buehler, M. Ajello, K. Bechtol, A. Bellini, M. Bolte, C. C. Cheung et al. "Discovery of a GeV blazar shining through the Galactic plane." The Astrophysical Journal Letters, Vol. 718, No. 2 (Aug., 2010): L166.