Fermi LAT detection of increasing gamma-ray activity of blazar MG2 J144640+3110
ATel #15888; Federica Giacchino (INFN Roma Tor Vergata & SSDC) on behalf of the Fermi Large Area Telescope Collaboration
on 4 Feb 2023; 23:34 UT
Credential Certification: Federica Giacchino (federica.giacchino@roma2.infn.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar
Referred to by ATel #: 15948
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed high-flux gamma-ray activity and the spectral hardening from a source positionally consistent with a blazar of unknown type, MG2 J144640+3110 (also known as 4FGL J1446.3+3111), with VLBI coordinates (J2000.0), R.A.: 221.6760 deg, Dec.: 31.1073 deg (J2000; Johnston et al. 1995, AJ, 110, 880).
Preliminary analysis indicates that on 2023 February 3, MG2 J144640+3110 was in a high state with a daily averaged gamma-ray flux (E>100 MeV) of (0.36 ± 0.11) e-6 photons cm^-2 s^-1 (statistical uncertainty only), about 40 times greater than the flux reported in the fourth Fermi-LAT source catalog (Abdollahi, S. et al. for the Fermi-LAT collaboration, ApJS 247, 33, 2020). The corresponding photon spectral index (E>100 MeV) of 2.07+/-0.23 (statistical uncertainty only) is smaller than the 4FGL catalog value of 2.57 +/- 0.08.
This is the first time that the Fermi-LAT Collaboration has announced flaring GeV gamma-ray behavior from MG2 J144640+3110.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of MG2 J144640+3110 will continue. This source has an entry in the FSSC light curve repository (https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.html?source_name=4FGL_J1446.3+3111#). We encourage multifrequency observations of this gamma-ray source. For this source, the Fermi-LAT contact person is F. Giacchino (federica.giacchino@roma2.infn.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.
