Fermi-LAT detection of gamma-ray flaring activity from the FSRQ PKS B0027-426
ATel #14648; A. Yusafzai (ECAP/FAU) and S. Garrappa (DESY-Zeuthen) on behalf of the Fermi Large Area Telescope Collaboration
on 20 May 2021; 20:16 UT
Credential Certification: Simone Garrappa (simone.garrappa@gmail.com)
Subjects: Gamma Ray, Request for Observations, AGN, Blazar
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 flat-spectrum radio quasar PKS B0027-426, also known as 4FGL J0030.3-4224 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 7.572886 deg, Decl. = -42.412912 deg (J2000; Petrov et al 2011 MNRAS, 414, 2528), and redshift z=0.495 (Hook et al. 2003 A&A, 399, 469).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on May 18 and May 19 2021 , with a daily averaged gamma-ray flux (E>100MeV) of (0.7+/-0.1) X 10^-6 photons cm^-2 s^-1 and (1.0+/-0.2) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), respectively. This corresponds to a flux increase of a factor of 19 and 29 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 1.8+/-0.1 for May 18 and 2.2+/-0.2 for May 19, and is significantly harder than the 4FGL value of 2.52+/-0.03 on both days.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. This source is being added to 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 Anke Yusafzai (Anke.yusafzai@fau.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.
