Fermi LAT detection of GeV flares in high redshift blazars 4C 38.41 (B2 1633+38) and PKS 0805-07

ATel #2136; S. Ciprini (University/INFN Perugia) on behalf of the Fermi Large Area Telescope Collaboration
on 23 Jul 2009; 15:25 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Stefano Ciprini (stefano.ciprini@pg.infn.it)

Tweet

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, detected on July 22, 2009 increasing gamma-ray activity from two sources, positionally consistent respectively with the EGRET flat spectrum radio quasar 4C 38.41, also known as B2 1633+38, OS 356, 3EG J1635+3813, 0FGL J1635.2+3809;  (RA: 16h 35m 15.493s, Dec. +38d 08m 04.50s, J2000.0,  ref. 1995, AJ, 110, 880,   redshift 1.814, ref. 2004, SDSS, release 3) and the gamma-ray flat spectrum radio quasar  PKS 0805-07 (RA: 08h 08m 15.536s, Dec -07d 51m 09.88s, J2000.0, ref. 1995, AJ, 110, 880,   redshift 1.837, ref. 1988, ApJ, 327, 561) discovered recently by Fermi LAT.

Preliminary analysis indicates that on July 22, 2009,  4C 38.41 appeared in a high state with a gamma-ray flux (E>100MeV) of  1.38+/-0.32 x 10^-6 photons cm^-2 s^-1 (statistical only).

Preliminary analysis indicates that on July 22, 2009,  PKS 0805-07 appeared in a high state with a gamma-ray flux (E>100MeV) of  1.60+/-0.33 x 10^-6 photons cm^-2 s^-1 (statistical only), almost a factor of 2 higher than the flux reported in the previous Fermi LAT ATel #2048.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of these sources will continue. In consideration of the ongoing gamma-ray activity, the rather high redshift and the superluminal motions of both the sources, we strongly encourage multiwavelength observations. For both the sources the Fermi LAT contact person is S. Ciprini (stefano.ciprini@pg.infn.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.