Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 0301-721
ATel #14293; R. Angioni (SSDC/INFN) on behalf of the Fermi Large Area Telescope Collaboration
on 26 Dec 2020; 17:59 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
Referred to by ATel #: 14918
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 0301-721, also known as 4FGL J0301.6-7155 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 45.410407 deg, Decl. = -71.942953 deg (J2000; Li & Jin 1996, A&AS, 120, 201), and redshift z=0.8232 (Titov et al. 2013, AJ, 146, 10).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on 25 December 2020, with a daily averaged gamma-ray flux (E>100MeV) of (7.9+/-1.2) X 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of 65 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 1.9+/-0.1, and is significantly smaller than the 4FGL value of 2.65+/-0.08. The source was detected on 24 December 2020 as well, with a daily averaged gamma-ray flux of (2.4+/-0.7) X 10^-7 photons cm^-2 s^-1 and a photon index 1.70+/-0.16. This hard-spectrum state was accompanied by the detection of a 13 GeV photon with probability >99% of having been emitted by PKS 0301-721, which was recorded at 2020-12-24 21:25:04.272 UTC.
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 Roberto Angioni (roberto.angioni@ssdc.asi.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.
