Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ OL 256
ATel #14233; I. Mereu (INFN Perugia) on behalf of the Fermi Large Area Telescope Collaboration
on 30 Nov 2020; 20:04 UT
Credential Certification: Isabella Mereu (mereuisabella@gmail.com)
Subjects: Gamma Ray, 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 enhanced gamma-ray flaring activity from a source positionally consistent with the flat-spectrum radio quasar OL 256, also known as 4FGL J1036.2+2202 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. =159.137 deg, Decl. = 22.053 deg (J2000; Petrov et al 2011, AJ, 142, 89), and redshift z=0.595 (Hewett & Wild 2010, MNRAS, 405, 2302).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on November 29, 2020, with a daily averaged gamma-ray flux (E>100MeV) of (7.6 +/- 1.7)X 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). The latter corresponds to a flux increase of a factor of 60 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). This is the highest LAT daily flux ever observed for this source. The corresponding photon index is 2.01+/- 0.15, and is significantly smaller than the 4FGL value of 2.61+/-0.08.
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 Isabella Mereu (mereuisabella@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.
