Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ AT20G J120741-010630
ATel #16627; Chiara Bartolini (University of Trento & INFN Bari) on behalf of the Fermi Large Area Telescope Collaboration
on 18 May 2024; 16:07 UT
Credential Certification: David J. Thompson (David.J.Thompson@nasa.gov)
Subjects: Gamma Ray, >GeV, AGN
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 AT20G J120741-010630, also known as 4FGL J1207.7-0106 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 181.923657 deg, Decl. = -1.110192 deg (J2000; Petrov et al., 2005, AJ, 129, 1163), and redshift z= 1.01 (Croom et al., 2004, MNRAS, 349, 1397).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on May 16, 2024, with a daily averaged gamma-ray flux (E>100MeV) of (4.3 +/- 1.4) X 10^-7 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of 55 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). The corresponding photon index is 2.5+/- 0.3, which is consistent with the 4FGL value of 2.33 ± 0.08 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 CTS 0490 can be accessed via the Fermi-LAT Light-Curve Repository at LCR (Abdollahi et al., 2023, ApJS, 265, 31). We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Chiara Bartolini (chiara.bartolini@ba.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.
