Fermi LAT Detection of a GeV Flare from the FSRQ S4 0954+65
ATel #6709; Felicia Krauss (Remeis Observatory & ECAP, FAU Erlangen/Univ. Wuerzburg) on behalf of the Fermi Large Area Telescope Collaboration
on 17 Nov 2014; 12:06 UT
Credential Certification: Felicia Krauss (Felicia.Krauss@fau.de)
Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray activity from a source positionally consistent with S4 0954+65 (RA: 149.696855, Dec: +65.565227, J2000, Johnston et al., 1995, AJ, 110, 880) at z = 0.368 (Wills et al., 1992, ApJ, 398, 454).
Preliminary analysis indicates that on Nov 15th, 2014, the daily averaged flux (E>100MeV) was (1.0 ± 0.2) × 10-6 photons cm-2 s-1 (errors are statistical only), which is the highest ever recorded for this source and is 28 times its average flux in the 2FGL catalog (2FGL J0958.6+6533; Nolan et al., 2012, ApJS, 199, 31). The source, which is included in the LAT hard source catalog (1FHL J0959.5+6535; Ackermann et al., 2013, ApJS, 209, 34), has a 2FGL photon index 2.42 ± 0.07, and 2.20±0.16 on Nov 15.
Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. This source is being added to the "LAT Monitored Sources" and a preliminary estimate 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 further multifrequency observations of this source. For this source the Fermi LAT contact person is Felicia Krauss (felicia.krauss@sternwarte.uni-erlangen.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.
