Fermi-LAT detection of second record flare of FSRQ PKS 1127-14
ATel #15731; R. J. Britto (University of the Free State), J. Valverde (UMBC/NASA GSFC) and G. La Mura (LIP, Portugal), on behalf of the Fermi Large Area Telescope Collaboration
on 30 Oct 2022; 13:39 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 renewed 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 radio coordinates R.A. = 172.529385 deg, Decl. = -14.824274 deg (J2000; Johnston et al. 1995, AJ, 110, 880), and redshift z=1.189 (Jones 2009, MNRAS, 399, 683).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on October 28, 2022 (MJD 59880), with a daily averaged gamma-ray flux (E>100MeV) of (3.6+/-0.5) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), and a peak 6-hour flux of (5.6+/-1.0) X 10^-6 photons cm^-2 s^-1 from 18:00-24:00 UTC (MJD 59880.75-59881.00). The former corresponds to a flux increase of a factor of about 130 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL-DR3, The Fermi-LAT collaboration 2022, ApJS, 260, 53). This could be the highest LAT daily flux ever observed for this source to this day, however compatible with the reported daily flux of May 12, 2022 at (2.9+/-0.4) X 10^-6 photons cm^-2 s^-1 (ATEL #15379). The daily photon index is 2.45+/-0.11, which remains consistent with the 4FGL-DR3 value of 2.60+/-0.04. The first report on Fermi-LAT observation of this source during gamma-ray flaring activity is in ATel #14260.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. Preliminary Fermi-LAT 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 at 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.
