Fermi LAT detection of increased gamma-ray activity from the high-redshift blazar PKS 0402-362
ATel #3655; F. D'Ammando (INAF-IASF Palermo and CIFS) on behalf of the Fermi Large Area Telescope Collaboration
on 23 Sep 2011; 07:31 UT
Credential Certification: Filippo D'Ammando (filippo.dammando@iasf-roma.inaf.it)
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 an increasing gamma-ray flux from a source positionally consistent with the flat spectrum radio quasar PKS 0402-362 (also known as 1FGL J0403.9-3603, Abdo et al. 2010, ApJS, 188, 405, and 2FGL J0403.9-3604, Abdo et al. 2011, submitted to ApJS, arXiv:11081435; RA: 04h03m53.7499s, Dec: -36d05m01.912s, J2000, Johnston et al. 1995, AJ, 110, 880) at redshift z = 1.417 (Peterson et al. 1976, ApJ, 207, 5).
Preliminary analysis indicates that the gamma-ray emission from PKS 0402-362 started to increase on 20 September 2011, with a daily gamma-ray flux (E > 100 MeV) of (0.9 +/- 0.3) x10^-6 ph cm^-2 s^-1 (statistical uncertainty only), reaching a peak flux of (3.8 +/- 0.5) x10^-6 ph cm^-2 s^-1 on 22 September. The peak flux represents an increase of a factor of 20 with respect to the average source flux observed in the first two years of Fermi mission (Abdo et al. 2011, submitted to ApJS, arXiv:11081435). High gamma-ray activity from this source was previously detected by Fermi-LAT (ATel #2413) and AGILE (ATel #2484).
Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage further multi-wavelength observations. For this source the Fermi LAT contact person is J. Vandenbroucke (justinv@stanford.edu).
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.
