[ Previous | Next | ADS ]

Fermi LAT detection of increased gamma-ray activity from the FSRQs PKS 2326-502 and B2 2308+34

ATel #2783; F. D’Ammando (INAF-IASF Palermo) on behalf of the Fermi Large Area Telescope Collaboration
on 9 Aug 2010; 16:55 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Filippo D'Ammando (filippo.dammando@iasf-roma.inaf.it)

Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar

Referred to by ATel #: 3008, 3024, 4225, 5477

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed an increasing gamma-ray flux from sources positionally consistent with the Flat Spectrum Radio Quasars PKS 2326-502 (1FGL J2329.2-4954, Abdo et al. 2010, ApJS, 188, 405; R.A.=23:29:20.880 Dec.=-49:55:40.68, J2000.0; z=0.518, Jauncey, D. L., et al. 1984, ApJ, 286, 498) and B2 2308+34 (1FGL J2311.0+3425, Abdo et al. 2010; R.A.=23:11:05.3288 Dec.=+34:25:10.905, J2000.0; z=1.817, Wills, D., Wills, B. J. 1976, ApJS, 31,143).

Preliminary analysis indicates that PKS 2326-502 on August 7, 2010, was in a high state with a daily gamma-ray flux (E > 100MeV) of (1.1+/-0.3)x10^-6 photons/cm^2/s (errors are statistical only), which represents an increase of a factor of about 15 with respect to the average source flux observed in the first eleven months of Fermi observations (Abdo et al. 2010).

Preliminary analysis indicates that also B2 2308+34 on August 7, 2010, was in a high state with a daily gamma-ray flux (E > 100 MeV) of (0.9+/-0.2)x10^-6 photons/cm^2/s (errors are statistical only), about 15 times the average source flux observed in the first eleven months of Fermi observations (Abdo et al. 2010). The source was detected at the same gamma-ray flux on August 8, 2010.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of these sources will continue. In consideration of the ongoing activity of these two sources we encourage multi-wavelength observations. For PKS 2326-502 and B2 2308+34 the Fermi LAT contact person is Filippo D’Ammando (dammando@ifc.inaf.it).

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.