[ Previous | Next | ADS ]

Fermi LAT detection of the first GeV gamma-ray flare from the BL Lac object TXS 2241+406

ATel #7126; Sara Buson on behalf of the Fermi Large Area Telescope Collaboration
on 23 Feb 2015; 10:43 UT
Credential Certification: Sara Buson (buson@pd.infn.it)

Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar

Referred to by ATel #: 8318

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 BL Lac object TXS 2241+406 (a.k.a. 3FGL J2244.1+4057, Acero et al. 2015, arXiv:1501.02003) at RA=341.05305 deg, Dec=40.95378 deg (J2000, Beasley et al. 2002, ApJS, 141, 13) with redshift z=1.171 (Shaw et al. 2012, ApJ, 748, 49).

Preliminary analysis indicates that on 2015 February 21, TXS 2241+406 was in a high state with daily averaged flux (E> 100 MeV) of (1.1+/-0.2)x10^-6 ph cm^-2 s^-1 and photon spectral index of 1.9+/-0.2 (errors are statistical only). This corresponds to a flux increase of a factor around 20 compared with the average flux reported in the third Fermi-LAT catalog.

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. Buson (sara.buson@unipd.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.