Fermi-LAT detection of enhanced gamma-ray activity from the FSRQ B2 1128+38
ATel #13670; L. Tomankova (ECAP/FAU), A. Yusafzai (ECAP/FAU), A. Gokus (Univ. Wuerzburg and ECAP/FAU), R. Angioni (SSDC/INFN) on behalf of the Fermi Large Area Telescope Collaboration
on 25 Apr 2020; 21:11 UT
Credential Certification: Roberto Angioni (r.angioni90@gmail.com)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
Referred to by ATel #: 13728
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 B2 1128+38, also known as 4FGL J1131.0+3815 (The Fermi-LAT collaboration 2020, ApJS, 247, 1), with coordinates R.A. = 172.722011 deg, Decl. = +38.255152 deg (J2000; Johnston et al. 1995, AJ, 110, 880), and redshift z=1.74 (Hewett & Wild 2010, MNRAS, 405, 2302).
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on April 24, 2020, with a daily averaged gamma-ray flux (E>100MeV) of (8.1 +/- 1.5) x 10^-7 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). This source has shown increased activity since 24 March 2020. The corresponding photon index is 2.2 +/- 0.2, and therefore significantly smaller than the 4FGL value of 2.55 +/- 0.05.
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 Lenka Tomankova (lenka.tomankova@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.
