Fermi-LAT detection of a new gamma-ray source associated with the quasar 3C 395
ATel #14383; M. Giroletti (INAF/IRA), R. Angioni (SSDC/INFN), C. C. Cheung (NRL), on behalf of the Fermi Large Area Telescope Collaboration
on 9 Feb 2021; 23:07 UT
Credential Certification: Teddy Cheung (Teddy.Cheung@nrl.navy.mil)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray emission from a source positionally consistent with the radio quasar 3C 395, also known as 4C +31.52 and B2 1901+31, with coordinates R.A. = 285.733079 deg, Decl. = 31.994917 deg (J2000; Johnston et al. 1995, AJ, 110, 880). 3C 395 is a known radio source showing superluminal motion (Lister et al. 2019, ApJ, 874, 43) and asymmetries between the parsec and kiloparsec scales (Lara et al. 1997, A&A, 319, 405). The redshift is 0.634 (Gelderman & Whittle 1994, ApJS, 91, 491). The source is not in any published LAT catalog and was not detected by AGILE or EGRET.
Preliminary analysis indicates that this source was significantly detected (>5 sigma) in a high gamma-ray state on 8 February 2021, with a daily averaged gamma-ray flux (E>100MeV) of (5.2+/-1.4) x 10^-7 photons cm^-2 s^-1 and a single power-law photon index of 2.7+/-0.3 (statistical uncertainties only). This corresponds to a flux increase of a factor of 60 relative to the preliminary flux based on an internal Fermi-LAT team 12-year catalog. An even higher flux of (1.2+/-0.3) x 10^-6 photons cm^-2 s^-1 was obtained for the 6-hr interval between 00-06 UT.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Marcello Giroletti (marcello.giroletti@inaf.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.
