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Title: The first γ-ray detection of the narrow-line Seyfert 1 FBQS J1644+2619

Here, we report the discovery of γ-ray emission from the narrow-line Seyfert 1 (NLSy1) galaxy FBQS J1644+2619 by the Large Area Telescope on board the Fermi satellite. The Third Fermi LAT Source catalogue reports an unidentified γ-ray source, detected over the first four years of Fermi operation, 0.°23 from the radio position of the NLSy1. Analysing 76 months of γ-ray data (2008 August 4–2014 December 31) we are able to better constrain the localization of the γ-ray source. The new position of the γ- ray source is 0.°05 from FBQS J1644+2619, suggesting a spatial association with the NLSy1. This is the sixth NLSy1 detected at high significance by Fermi-LAT so far. Notably, a significant increase of activity was observed in γ-rays from FBQS J1644+2619 during 2012 July–October, and an increase of activity in V -band was detected by the Catalina Real-Time Sky Survey in the same period.
 [1] ;  [2] ;  [3] ;  [2]
  1. Univ. di Bologna (Italy). Dip. di Fisica e Astronomia; Istituto Nazionale di Astrofisica (INAF), Bologna (Italy). Istituto di Radioastronomia
  2. Istituto Nazionale di Astrofisica (INAF), Bologna (Italy). Istituto di Radioastronomia
  3. KTH Royal Inst. of Technology, Stockholm (Sweden). Oskar Klein Centre, Dept. of Physics
Publication Date:
Grant/Contract Number:
AC02-76SF00515; NNG05GF22G; AST-0909182; AST- 1313422
Accepted Manuscript
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Volume: 452; Journal Issue: 1; Journal ID: ISSN 0035-8711
Royal Astronomical Society
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); Swedish Research Council (SRC); Japan Aerospace Exploration Agency (JAXA)
Contributing Orgs:
Fermi LAT Collaboration
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; galaxies; gamma-rays; FBQS 1644+2619
OSTI Identifier: