[ Previous | Next | ADS ]

Fermi LAT Detection of a Gamma-ray Flare from the active galaxy PKS 0903-57

ATel #7704; Bryce Carpenter (CUA/NASA/GSFC) and Roopesh Ojha (NASA/GSFC/UMBC) on behalf of the Fermi Large Area Telescope Collaboration
on 24 Jun 2015; 14:27 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

Subjects: Gamma Ray, >GeV, AGN, Blazar

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux from a source positionally consistent with the active galaxy PKS 0903-57 (RA: 09h04m53.1790s, Dec: -57d35m05.783s, J2000, Fey et al., 2004, AJ, 128, 2593) at z = 0.695 (Thompson et al., 1990, PASP, 102, 1235). This source is considered a blazar candidate of unknown type (BCU) in the Fermi LAT 4-Year Point Source Catalog (3FGL; Acero et al. 2015, ApJS, 218, 23).

Preliminary analysis indicates that on June 22, 2015, the daily averaged flux (E>100MeV) was (1.2 +/- 0.3) x 10^-6 photons cm^-2 s^-1 (errors are statistical only), which is about 30 times its average flux in the 3FGL catalog (3FGL J0904.8-5734). Its spectral index of 1.85 +/- 0.15 is significantly harder than the 3FGL value of 2.25 +/- 0.05.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage further multifrequency observations of this source. For this source the Fermi LAT contact person is Bryce Carpenter (carpbr01@gmail.com).

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.