Fermi-LAT Detection of a New Gamma-Ray Source Fermi J0607.8+0843, Likely Associated with TXS 0605+086
ATel #17684; S. Rani (Michigan Technological University), T. Lewis (Michigan Technological University), G. La Mura (INAF - Astronomical Observatory of Cagliari), C. C. Teddy Cheung (NRL) on behalf of the Fermi Large Area Telescope Collaboration
on 16 Feb 2026; 22:18 UT
Credential Certification: Israel Martinez (imc@umd.edu)
Subjects: Gamma Ray, >GeV
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has detected gamma-ray emission from a previously unreported source at Galactic latitude b = -5.54 deg, designated Fermi J0607.8+0843. The best-fit coordinates are R.A. = 92.05 deg, Dec. = 8.62 deg (J2000), with a 95% confidence error radius of 0.24 deg.
Preliminary analysis indicates that this source was significantly detected on February 14, 2026, with a daily averaged gamma-ray flux (E > 100 MeV) of (1.2 +/- 0.3) e-06 photons cm^-2 s^-1 (statistical uncertainty only). The corresponding photon index of 2.5 +/- 0.2 indicates a relatively soft spectrum.
A search for counterparts within the LAT localization region reveals the compact VLBI radio source TXS 0605+086 (J0608+0840), located 0.05 deg from the LAT best-fit position and well within the 95% confidence region. Its VLBI coordinates are R.A. = 06:08:13.011, Dec. = +08:40:25.204 (J2000; Petrov & Kovalev 2025, ApJS, 276, 38). TXS 0605+086 has not previously been reported as a gamma-ray emitter.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. Multiwavelength observations during the ongoing activity of this source are strongly encouraged. The Fermi LAT contact persons are C. C. Teddy Cheung (chi.c.cheung2.civ@us.navy.mil) and Giovanni La Mura (giovanni.lamura@inaf.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
