Fermi-LAT detection of a new gamma-ray source associated with the radio source 4C +49.29
ATel #17048; G. La Mura (INAF - Astronomical Observatory of Cagliari), P. Monti-Guarnieri (University of Trieste and INFN - Trieste), on behalf of the Fermi Large Area Telescope Collaboration
on 21 Feb 2025; 18:23 UT
Credential Certification: Giovanni La Mura (giovanni.lamura@inaf.it)
Subjects: Gamma Ray, Request for Observations, AGN
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray emission from a source positionally consistent with the radio source 4C +49.29, also known as TXS 1729+491, with coordinates R.A. = 262.68575 deg, Dec. = +49.10719 deg (J2000; Becker et al. 1991, ApJS, 75, 1), and redshift z=1.038 (Walsh et al. 1984, MNRAS, 211, 105). This source is not in any published LAT catalog and was not detected by AGILE or EGRET.
Preliminary analysis indicates that this source was significantly detected (>5 sigma) in a high gamma-ray state on February 20, 2025, with a daily averaged gamma-ray flux (E>100MeV) of (0.4+/-0.1) x 10^-6 photons cm^-2 s^-1 and a single power-law photon index of 2.1+/-0.2 (statistical uncertainties only).
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Giovanni La Mura (giovanni DOT lamura AT inaf DOT 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.
