Fermi-LAT detection of renewed gamma-ray activity from PKS 1824-582
ATel #14013; Anke Yusafzai (ECAP/FAU), Roberto Angioni (SSDC/INFN), Stefano Ciprini (SSDC/INFN), Sara Buson (Univ. Wuerzburg), on behalf of the Fermi Large Area Telescope Collaboration
on 15 Sep 2020; 18:45 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 renewed gamma-ray flaring activity from a source positionally consistent with the extragalactic radio source PKS 1824-582, also known as 4FGL J1829.2-5813, with coordinates RA=277.7622 deg, Dec=-58.2272 deg (J2000; Fey et al. 2006, AJ, 132, 1944). This source is classified as an FSRQ at a redshift of 1.531 (Healey et al. 2008, ApJS, 175, 97).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state during the past six days, reaching a daily averaged gamma-ray flux (E>100MeV) of (1.2+/-0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only) on 14 September 2020. The latter corresponds to a flux increase of a factor of 16 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). The corresponding photon index is 2.5+/-0.2, and is consistent with the 4FGL value of 2.56+/-0.02 within the uncertainties. This source was discovered in 2014 April (ATel #6067) and showed a fast variability in 2016 September (ATel #9471).
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. This source is part of the "LAT Monitored Sources" and consequently, a preliminary estimation of the daily gamma-ray flux observed by Fermi-LAT is publicly available ( http://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/ ). We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Sara Buson (buson@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.
