Fermi-LAT detection of a new gamma-ray source associated with the high-redshift FSRQ CGRaBS J1933+6540
ATel #11886; C. C. Cheung (NRL), on behalf of the Fermi-LAT collaboration
on 24 Jul 2018; 21:35 UT
Credential Certification: Teddy Cheung (Teddy.Cheung@nrl.navy.mil)
Subjects: Gamma Ray, >GeV, AGN, Blazar
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 positionally consistent with the Flat-Spectrum Radio Quasar (FSRQ) CGRaBS J1933+6540, also known as TXS 1933+655, with coordinates R.A. = 293.4889050 deg, Decl. = 65.6713411 deg (J2000; Beasley et al. 2002 ApJS 141, 13), at redshift, z=1.687 (Healey et al. 2008 ApJS 175, 97). This source is not in any published LAT catalog and was not detected by AGILE or EGRET.
Preliminary analysis indicates that this source went into a high-flux state on 2018 July 23, with a daily averaged gamma-ray flux (E>100MeV) of (0.6+/-0.1) x 10^-6 photons cm^-2 s^-1 (statistical uncertainties only; single power-law photon index of 2.3+/-0.2), with a peak 6-hr flux from 12:00-18:00 UTC of (1.0+/-0.3) x 10^-6 photons cm^-2 s^-1.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage further multifrequency observations of this source. The Fermi-LAT contact person for this source is C. C. Cheung (teddy.cheung@nrl.navy.mil).
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.
