Fermi-LAT detection of renewed gamma-ray activity from the FSRQ OQ 334
ATel #17504; C. Bartolini (University of Trento & INFN Bari), on behalf of the Fermi Large Area Telescope Collaboration
on 21 Nov 2025; 15:14 UT
Credential Certification: Chiara Bartolini (chiara.bartolini-1@unitn.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray renewed activity from a source positionally consistent with the flat spectrum radio quasar (FSRQ) OQ 334, also known as B2 1420+32, GB2 1420+326 and 4FGL J1422.5+3223 (Abdollahi et al. 2022, ApJS, 260, 53), with radio coordinates R.A: 215.62657 deg, Dec.: 32.38623 deg; (J2000; Petrov & Taylor 2011, AJ, 142, 89), and a redshift z=0.6819 (Hewett & Wild 2010, MNRAS, 405, 2302).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on November 20, 2025, with a daily averaged gamma-ray flux (E>100MeV) of (1.2 +/- 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 data release of the fourth Fermi-LAT catalog (4FGL-DR4, Ballet et al. 2023, arXiv:2307.12546). The corresponding photon index is 2.0+/-0.1, indicating a harder spectrum than the 4FGL-DR4 value of 2.24+/-0.01. The Fermi-LAT collaboration has previously reported gamma-ray flaring activity positionally consistent with this source in ATels #12277, #12942, #13382, and #16680.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. A preliminary light curve for OQ 334 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 Stefano Ciprini (stefano.ciprini[at]roma2.infn.it) and C. C Cheung (Teddy.Cheung@nrl.navy.mil).
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.
