Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 0208-512

ATel #13320; R. Angioni (SSDC/INFN) on behalf of the Fermi-LAT collaboration
on 1 Dec 2019; 00:28 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)

Subjects: Gamma Ray, >GeV, AGN, 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 PKS 0208-512, also known as 4FGL J0210.7-5101 (The Fermi-LAT collaboration 2019, arXiv:1902.10045), with coordinates R.A. = 32.692502 deg, Decl. = -51.017192 deg (J2000; Johnston et al. 1995, AJ, 110, 880), and redshift z=0.999 (Wisotzki et al. 2000, A&A, 358, 77).

Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on 29 November 2019, with a daily averaged gamma-ray flux (E>100MeV) of (1.1+/-0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). The latter corresponds to a flux increase of a factor of 13 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). This is comparable to the previous highest LAT daily flux ever observed for this source in May 2011 (ATel #3338). The corresponding photon index is 2.1+/-0.1, and is significantly smaller than the 4FGL value of 2.35+/-0.01. A ~22 GeV photon with a probability greater than 99% of being emitted by PKS 0208-512 has also been detected.

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 will be 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 W. Collmar (wec@mpe.mpg.de).

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.