Fermi-LAT detection of a new flaring gamma-ray source Fermi J1153-1124
ATel #12206; M. Giroletti and G. Principe (INAF-IRA) on behalf of the Fermi Large Area Telescope Collaboration
on 13 Nov 2018; 01:23 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar
The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray emission from a source (Fermi J1153-1124) with coordinates R.A. = 178.44 deg, Decl. = -11.11 deg (J2000) and 95% confidence error radius of 0.22 deg. Fermi J1153-1124 is not in any published LAT catalog and was not detected by AGILE or EGRET. The error circle contains a flat spectrum radio quasar, PKS J1153-1105, located at z=0.269, which is also a VLBI calibrator.
Preliminary analysis indicates that Fermi J1153-1124 went into a high flux state on November 10, 2018, and further brightened on November 11, 2018 reaching a daily averaged gamma-ray flux (E>100MeV) of (1.0+/-0.2) X 10^-6 photons cm^-2 s^-1 with a single power-law photon index of 2.34+/-0.12 (statistical uncertainty only).
Because this is a new detection of this source, we strongly encourage further multifrequency observations of this object. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. Fermi J1153-1124 is being added to the "LAT Monitored Sources" and consequently a preliminary estimation of the daily gamma-ray flux observed by Fermi-LAT will be publicly available (http://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/). The Fermi-LAT contact person for this source is G. Principe (principe@ira.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.
