Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 1127-14
ATel #15379; B. Rani (KASI, S. Korea), J. Valverde (UMBC/NASA GSFC), and G. La Mura (LIP, Portugal), on behalf of the Fermi Large Area Telescope Collaboration
on 14 May 2022; 00:00 UT
Credential Certification: Janeth Valverde (valverde@llr.in2p3.fr)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray activity from a source positionally consistent with the flat-spectrum radio quasar PKS 1127-14, also known as 4FGL J1129.8-1447 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A. = 172.529385 deg, Decl. = -14.824274 deg (J2000; Johnston et al. 1995, AJ, 110, 880), and redshift z=1.184 (Wilkes 1986, MNRAS, 218, 331).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on May 12, 2022, with a daily averaged gamma-ray flux (E>100MeV) of (2.9+/-0.4) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), and a peak 6-hour flux of (6.4+/-1.0) X 10^-6 photons cm^-2 s^-1 from 12:00-18:00 UTC. The former corresponds to a flux increase of a factor of 120 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). This is the highest LAT daily flux ever observed for this source. The daily photon index is 2.6+/-0.1, and is consistent with the 4FGL value of 2.69+/-0.06 within the uncertainties. The flare triggered the Fermi-LAT Monitor alert system, which issued a GCN/Fermi_LAT_MON Notice (https://gcn.gsfc.nasa.gov/other/1652453417_fermi.txt). Fermi-LAT observations for this source during previous gamma-ray flaring activity are reported in ATel #14260.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. Preliminary light curves can be accessed via the Monitored Source List at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/source/PKS_1127-14, and via the Fermi-LAT Light-Curve Repository at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/lcr/source.html?source_name=4FGL_J1129.8-1447. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Bindu Rani (binduphysics@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.
