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Fermi LAT detection of a GeV flare from the FSRQ PKS 1004-217

ATel #10952; Janeth Valverde (LLR/Ecole Polytechnique) and Roopesh Ojha (NASA/GSFC/UMBC) on behalf of the Fermi Large Area Telescope Collaboration
on 11 Nov 2017; 14:24 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

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

Referred to by ATel #: 11122, 11378

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed an increasing gamma-ray flux from a source positionally consistent with the flat spectrum radio quasar (FSRQ) PKS 1004-217 with coordinates RA: 10h06m46.4136s, DEC: -21d59m20.410s, J2000 (Beasley et al. 2002, ApJS, 141, 13) and redshift z=0.330 (Browne & Savage, 1977, MNRAS, 179, 65).

Preliminary analysis indicates that on 8 November 2017 and 9 November 2017, this source was in a high-flux state with a daily averaged gamma-ray flux (E>100MeV) of (0.5+/-0.1) X 10^-6 photons cm^-2 s^-1 and (0.5+/-0.1) X 10^-6 photons cm^-2 s^-1, respectively (statistical uncertainties only). These values are about a factor of 14 greater than the average flux reported in the third Fermi LAT catalog (3FGL; Acero et al. 2015, ApJS, 218, 23). The corresponding photon spectral index of 2.4+/-0.3 and 2.2+/-0.2, respectively, is in the typical range for a Fermi blazar.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source we strongly encourage multiwavelength observations. For this source the Fermi LAT contact person is Janeth Valverde (valverde@llr.in2p3.fr).

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.