Fermi-LAT detection of renewed gamma-ray activity from the FSRQ OQ 334

ATel #17790; F. Giacchino (USAL - Universidad de Salamanca, Spain, and INFN - Rome Tor Vergata, Sapienza University Rome) and G. La Mura (INAF - O. A. Cagliari), on behalf of the Fermi Large Area Telescope Collaboration
on 10 May 2026; 17:01 UT
Credential Certification: Federica Giacchino (federica.giacchino@roma2.infn.it)

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The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed renewed gamma-ray 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 May 9, 2026, with a daily averaged gamma-ray flux (E>100MeV) of (3.0 +/- 0.3) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to a flux increase of a factor of more than 40 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 2.1+/-0.1, indicating a slightly harder spectral state than the one corresponding to 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 #17654, #17504, #16680, #13382, #12942 and #12277.

Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. Because OQ 334 belongs to the list of LAT daily monitored sources, a preliminary light curve is available at OQ 334. The light curve of this source can also be accessed through the Fermi Light Curve Repository at 4FGL J1422.3+3223. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact persons are Stefano Ciprini (stefano.ciprini[at]roma2.infn.it) and Teddy Cheung (chi.c.cheung2.civ[at]us.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.