Fermi-LAT detection of enhanced gamma-ray activity from the BL Lac NVSS J142750-321515
ATel #15104; G. La Mura (LIP, Portugal), on behalf of the Fermi Large Area Telescope Collaboration
on 11 Dec 2021; 08:04 UT
Credential Certification: Giovanni La Mura (glamura@lip.pt)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Transient
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 BL Lac source NVSS J142750-321515, also known as 4FGL J1427.7-3215 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 216.959 deg, Decl. = -32.255 deg (J2000; D'Abrusco R. et al., 2014, ApJS, 215, 14) and unknown redshift.
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on December 8, 2021, with a daily averaged gamma-ray flux (E>100MeV) of (0.37+/-0.17) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of 70 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 2.2+/-0.3 and is consistent with the 4FGL value of 2.1+/-0.1 within the uncertainties.
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 Giovanni La Mura ( glamura AT lip DOT pt ).
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.
