Fermi-LAT detection of a new gamma-ray source associated with the FSRQ 4C +25.01
ATel #14294; R. Angioni (SSDC/INFN) on behalf of the Fermi Large Area Telescope Collaboration
on 27 Dec 2020; 17:37 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)
Subjects: Gamma Ray, >GeV, Request for Observations, 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 flat-spectrum radio quasar 4C +25.01, also known as PKS 0017+25 and GB6 J0019+2602, with coordinates R.A. = 4.915752 deg, Decl. = 26.047855 deg (J2000; Beasley et al. 2002, ApJS, 141, 13), and redshift z=0.2836 (Dong et al. 2018, AJ, 155, 189), a known VLBI source. This 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 26 December 2020, with a daily averaged gamma-ray flux (E>100MeV) of (3.5+/-1.2) X 10^-7 photons cm^-2 s^-1 and a single power-law photon index of 2.0+/-0.2 (statistical uncertainties only). The gamma-ray source is marginally detected (>3 sigma) in the time interval 2020-12-26 18:00:00 - 2020-12-27 00:00:00 UTC as well, with averaged gamma-ray flux of (6+/-3) X 10^-7 photons cm^-2 s^-1 and a single power-law photon index of 1.9+/-0.2.
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 Roberto Angioni (roberto.angioni@ssdc.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.
