Fermi-LAT detection of enhanced gamma-ray activity from the BL Lac source MG2 J043337+2905
ATel #16079; J. Forman (SURA / CRESST II / NASA GSFC), I. Mereu (INFN Perugia), J. Valverde (UMBC/ NASA GSFC), on behalf of the Fermi Large Area Telescope Collaboration
on 10 Jun 2023; 23:16 UT
Credential Certification: Janeth Valverde (valverde@llr.in2p3.fr)
Subjects: Gamma Ray, >GeV, 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 BL Lac MG2 J043337+2905, also known as 4FGL J0433.6+2905 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 68.407624 deg, Decl. = 29.098744 deg (Fey et al. 2004, AJ, 127, 3587), and redshift z=0.970 (Mishra et al. 2018, MNRAS, 473, 5154).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on June 8, 2023 , with a daily averaged gamma-ray flux (E>100MeV) of (6.4+/-2.0) X 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of 30 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+/-0.2, indicating a harder spectrum than the 4FGL value of 2.11+/-0.03.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. A preliminary light curve can be accessed via the Fermi-LAT Light-Curve Repository at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/lcr/source.html?source_name=4FGL_J0433.6+2905. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Jordan Forman (jforman2018@my.fit.edu).
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.
