Fermi-LAT detection of the first GeV gamma-ray flare from the BL Lac object ON 246 (S3 1227+25)
ATel #6982; Sara Cutini (ASDC/INFN), Dario Gasparrini (ASDC/INFN), on behalf of the Fermi-LAT collaboration
on 23 Jan 2015; 17:50 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@asdc.asi.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope, has observed for the first time on daily timescales gamma-ray outburst activity from a source positionally consistent with the bright optically peaked BL Lac object ON 246 (RA=187.55871 deg, Dec=25.30198 deg, J2000, Beasley et al. 2002, ApJS, 141, 13; with redshift z=0.135, Nass et al. 1996, A&A, 309, 419), also known as 3FGL J1230.3+2519 (Acero et al. 2015, arXiv:1501.02003).
The source has been detected on 22 January 2015 with daily averaged flux (E> 100 MeV) of (0.6+/-0.2)x10^-6 ph cm^-2 s^-1 with a photon spectral index of 2.2+/-0.3 (errors are statistical only). This corresponds to a flux increase of a factor around 31 compared with the average flux reported in the third Fermi-LAT catalog (3FGL).
Since Fermi operates in all-sky survey mode, gamma-ray monitoring of this source will continue. In consideration of the activity of this source we strongly encourage multi-wavelength observations. The Fermi LAT contact person for this source is S. Cutini (sara.cutini@asdc.asi.it)
The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
