Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PMN J0231-4746
ATel #13209; G. Principe (IRA-INAF) and R. Angioni (SSDC/INFN) on behalf of the Fermi Large Area Telescope Collaboration
on 21 Oct 2019; 15:07 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)
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 enhanced gamma-ray flaring activity from a source positionally consistent with the flat-spectrum radio quasar PMN J0231-4746, also known as 4FGL J0231.2-4745 (The Fermi-LAT collaboration 2019, arXiv:1902.10045), with coordinates R.A. = 37.799250 deg, Decl. = -47.769778 deg and redshift z=0.76500 (Healey S. E. et al. 2008, ApJS, 175, 97).
Preliminary analysis indicates that this source has been in an elevated gamma-ray emission state in the last three days, starting from October 17, and reaching a daily averaged gamma-ray flux (E>100MeV) of (0.8+/-0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only) on October 19. 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 2.3+/-0.2, and is significantly smaller than the 4FGL value of 2.8+/-0.1.
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 Giacomo Principe (giacomo.principe@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.