Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ PKS 1335-127
ATel #13741; A. Yusafzai (ECAP/FAU), L. Tomankova (ECAP/FAU) on behalf of the Fermi Large Area Telescope Collaboration
on 18 May 2020; 18:02 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)
Subjects: >GeV, Request for Observations, AGN, Blazar, Quasar
Referred to by ATel #: 13771
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray flaring activity from a source positionally consistent with the flat-spectrum radio quasar PKS 1335-127, also known as 4FGL J1337.6-1257 (The Fermi-LAT collaboration 2020, ApJS, 247, 1), with coordinates R.A. = 204.4770 deg, Decl. = -13.2854 deg (J2000; Johnston et al. 1995, AJ, 110, 880), and redshift z = 0.539 (Stickel, Kuhr, Fried 1993, A&AS, 97, 483).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on May 17, 2020, with a daily averaged gamma-ray flux (E>100MeV) of (1.1 +/- 0.3) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). The latter corresponds to a flux increase of a factor of ~35 relative to the average flux reported in the fourth Fermi-LAT catalog (4FGL). The corresponding photon index is 2.3 +/- 0.2, and therefore smaller than the 4FGL value of 2.40 +/- 0.03.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. This is the first GeV flare detected from PKS 1335-127 since the beginning of the Fermi mission. Consequently, this source is being added to the list of LAT monitored sources. Going forward, 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/). We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Anke Yusafzai (anke.yusafzai@fau.de).
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.
