Fermi-LAT Detection of Gamma-ray Emission from the FSRQ B2 1846+32B
ATel #8315; Roopesh Ojha (NASA/GSFC/UMBC), Bryce Carpenter (CUA/NASA/GSFC) and Sara Buson (NASA/GSFC/UMBC) on behalf of the Fermi Large Area Telescope Collaboration
on 21 Nov 2015; 15:59 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar
The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed a hard spectrum gamma-ray flare from a source positionally consistent with the flat spectrum radio quasar (FSRQ) B2 1846+32B with coordinates RA: 18h48m34.3611s, Dec: 32d44m00.139s, J2000, (Beasley et al. 2002, ApJS, 141, 13) at z=0.981 (Massaro et al. 2015, ApJS, 217, 2).
Preliminary analysis indicates that on 19 November 2015 this source was in a high-flux state, with a daily averaged gamma-ray flux (E>100MeV) of (1.0+/-0.1) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). This source is not included in the LAT 4-year point source catalog (3FGL; Acero et al. 2015, ApJS 218, 23) but appears in the 2FGL (2FGL J1848.6+3241; Nolan et al. 2012, ApJS, 199, 31). The corresponding photon spectral index of 1.9+/-0.1 is significantly harder than its 2FGL index (2.4+/-0.1).
Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage further multifrequency observations of this source. For this source the Fermi LAT contact person is Roopesh Ojha (Roopesh.Ojha@gmail.com).
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.
