Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 0202-17
ATel #14801; I. Mereu (INFN Perugia), J. Valverde (UMBC/NASA GSFC), on behalf of the Fermi-LAT Collaboration
on 20 Jul 2021; 10:30 UT
Credential Certification: Isabella Mereu (mereuisabella@gmail.com)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
Referred to by ATel #: 15311
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray activity from a source positionally consistent with the FSRQ PKS 0202-17, also known as 4FGL J0205.0-1700 (The Fermi-LAT collaboration 2020, ApJS, 247, 1), with coordinates R.A. = 31.2403096 deg, Decl. = -17.0221778 deg (J2000; Fey et al. 2004, AJ, 128, 2593), and redshift z= 1.739 (Jones et al. 2009, MNRAS, 399, 683).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on July 18, 2021, with the highest-energy detected photon having energy 12 GeV (2021-07-18 15:53:02.934 UTC) and with a daily averaged gamma-ray flux (E>100MeV) of (6.6 +/- 1.5) X 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). The latter corresponds to an increase of a factor of 20 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 2.4 +/- 0.2, smaller than the 4FGL value of 2.70 +/- 0.04.
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.
