Fermi-LAT detection of enhanced gamma-ray activity from the BL Lac PMN J0334-3725
ATel #17153; Omer Faruk Coban (Institute of Space Sciences, ICE-CSIC), on behalf of the Fermi Large Area Telescope Collaboration
on 18 Apr 2025; 16:17 UT
Credential Certification: Giovanni La Mura (giovanni.lamura@inaf.it)
Subjects: Gamma Ray, 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 BL Lac object PMN J0334-3725, also known as 4FGL J0334.2-3725 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 53.56427 deg, Dec. = -37.42863 deg (J2000; Hunt et al. 2021, AJ, 162, 18), and redshift z = 0.230 (Narendra et al. 2022, ApJS, 259, 16).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on April 17, 2025, with a daily averaged gamma-ray flux (E>100MeV) of (0.4 +/- 0.1) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of 20 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 2.1+/-0.2, and is consistent with the 4FGL value of 2.02+/-0.02 within the uncertainties.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. A preliminary light curve for PMN J0334-3725 can be accessed via the Fermi-LAT Light-Curve Repository. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Omer Faruk Coban (coban@ice.csic.es).
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.
