Fermi-LAT detection of increasing gamma-ray activity from blazar PKS 2054-377
ATel #15947; Federica Giacchino (INFN Roma Tor Vergata & SSDC) on behalf of the Fermi Large Area Telescope Collaboration
on 15 Mar 2023; 21:58 UT
Credential Certification: Federica Giacchino (federica.giacchino@roma2.infn.it)
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 an increasing gamma-ray flux from a source positionally consistent with flat-spectrum radio source PKS 2054-377, also known as NVSS J205741-373402 (Healey et al. 2007 ApJS, 171, 61), centered on the coordinates R.A. = 314.465 deg, Decl. = -37.6102 deg (J2000; Petrov et al. 2007 AJ, 133, 1236) with 68% and 95% containment radii of 0.11 deg and 0.18 deg, respectively. The redshift is z=1.071 (Jackson et al. 2002 A&A, 386, 97). This source is not in any published LAT catalog.
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on 2023 March 14 with a 1-day average gamma-ray flux (E>100MeV) of (2.7 +/- 1.2) x 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). The corresponding photon index is 2.1 +/- 0.3.
Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source we will keep searching in the next days for any delayed gamma-ray activity. For this source the Fermi LAT contact person is Federica Giacchino (fgiacchi@roma2.infn.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.
