Fermi-LAT detection of a new gamma-ray source associated with the flat spectrum radio source TXS 2023+503
ATel #16522; I. Mereu (INFN Perugia), P. Benke (MPIfR), C. C. Cheung (NRL), on behalf of the Fermi Large Area Telescope Collaboration
on 12 Mar 2024; 05:26 UT
Credential Certification: Isabella Mereu (mereuisabella@gmail.com)
Subjects: >GeV, Request for Observations, AGN, Blazar, Quasar, Transient
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 flat spectrum radio source TXS 2023+503 with coordinates R.A. = 306.35405 deg, Decl. = 50.47764 deg (J2000; Beasley et al. 2002, ApJS, 141, 13). 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 March 9, 2024 with a daily averaged gamma-ray flux (E>100MeV) of (8.0 +/- 1.9) X 10^-7 photons cm^-2 s^-1 and a single power-law photon index of 1.84 +/- 0.13 (statistical uncertainties only). Two E>10 GeV photons (up to about 30 GeV) were detected with a probability >99% of being produced by the gamma-ray source.
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 Isabella Mereu (mereuisabella@gmail.com).
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.
