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Fermi LAT Detection of a GeV Flare from the Blazar 4C +01.28

ATel #5909; Felicia Krauss (Remeis Observatory & ECAP, FAU Erlangen/Univ. Wuerzburg), Bryce Carpenter (CUA/NASA/GSFC) on behalf of the Fermi Large Area Telescope Collaboration
on 20 Feb 2014; 16:09 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

Subjects: Gamma Ray, >GeV, AGN, Black Hole, Blazar, Quasar

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with 4C +01.28 (also known as PKS 1055+018) RA=10h58m29.6052s, Dec=+01d33m58.824s (J2000; Johnston et al. 1995, AJ, 110, 880) at z= 0.888 (Wills and Lynds 1978, ApJS, 36, 317).

Preliminary analysis indicates that on Feb 18th, 2014, the daily averaged flux (E>100MeV) was (1.0 +/- 0.3) x 10^-6 photons cm^-2 s^-1 (errors are statistical only), which is the highest ever recorded for this source and is 11 times its average flux in the 2FGL catalog (2FGL J1058.4+0133; Nolan et al. 2012, ApJS, 199, 31).

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.