Fermi-LAT detection of a new gamma-ray source associated with the flat-spectrum radio source PMN J1712-0501
ATel #16389; C. C. Cheung (NRL), D. Kocevski (NASA/MSFC), on behalf of the Fermi Large Area Telescope Collaboration
on 22 Dec 2023; 20:36 UT
Credential Certification: Teddy Cheung (Teddy.Cheung@nrl.navy.mil)
Subjects: >GeV, AGN, Blazar
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 PMN J1712-0501, with radio coordinates R.A. = 258.21813 deg, Decl. = -5.02789 deg (J2000; Healey et al. 2007, ApJS, 171, 61), and unknown redshift. 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 in the week of 2023 December 11.0-18.0, with a weekly averaged gamma-ray flux (E>100MeV) of (1.8+/-1.0) X 10^-7 photons cm^-2 s^-1 and a single power-law photon index of 1.9+/-0.2 (statistical uncertainties only). Three high-energy photons (E = 10 to 12 GeV) were detected during the 1-week interval. The transient was identified through the "Fermi All-sky Variability Analysis" that searches the sky for high-energy transients on weekly time scales (Ackermann et al. 2013, ApJ, 771, 57).
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 C.C. Cheung (Teddy.Cheung _at_ 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.
