[ Previous | Next | ADS ]

Fermi LAT detection of increasing gamma-ray activity of blazar PKS 0454-234

ATel #1898; E. Cavazzuti (ASI Science Data Center), E. Hays (NASA/GSFC); on behalf of the Fermi Large Area Telescope Collaboration
on 12 Jan 2009; 08:18 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Gino Tosti (tosti@pg.infn.it)

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

Referred to by ATel #: 3703, 3722

The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope (formerly GLAST, launched June 11, 2008), has observed a continuous and increasing trend in the gamma-ray flux from a source positionally consistent with the blazar PKS 0454-234 (Position J2000.0: RA:04h57m03.2s, Dec:-23d24m52s, Johnston, K. J et al., 1995, AJ, 110,880J, redshift 1.003, M. Stickel et al., 1989A&AS, 80, 103S). PKS 0454-234 is a flat-spectrum radio source previously identified with the EGRET gamma-ray source 3EG J0456-2338 (Hartman et al. 1999, ApJS, 123, 79H).

Preliminary analysis indicates that the source is in a high state with a gamma-ray flux (E>100MeV) on January 11, 2009 of (1.96+/-0.30) x10-6 photons cm-2 s-1. This is the highest daily-averaged flux measured from this source since launch. The Fermi light curve of last few days shows rapid flares, up to (2.83 +/- 0.59) x10-6 photons cm-2 s-1, that deserve to be monitored.

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 Dario Gasparrini (dario.gasparrini@asdc.asi.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.