Swift observations of the flaring blazar B3 0650+453
ATel #3609; K. Sokolovsky (ASC Lebedev/SAI MSU), F. D'Ammando (INAF-IASF Palermo and CIFS) on behalf of the Fermi Large Area Telescope Collaboration
on 30 Aug 2011; 18:39 UT
Credential Certification: Kirill Sokolovsky (ksokolov@mpifr-bonn.mpg.de)
Subjects: Optical, Ultra-Violet, X-ray, AGN, Blazar, Quasar
Following the reported flaring activity of the flat spectrum radio quasar B3 0650+453 in GeV (ATel #3580) and radio (ATel #3596) bands, Swift observations of the source were performed on 2011 August 27, five days after the peak of the gamma-ray flare.
Swift/XRT data were taken in Photon Counting mode for a net exposure of 5.1 ksec. The X-ray spectrum can be fit by an absorbed power law with the HI column density fixed to the Galactic value of N_HI = 8.72 x 10^20 cm^-2 (Kalberla et al. 2005, A&A, 440, 775), and the photon index Gamma = 1.8+/-0.2. The unabsorbed 0.3-10 keV flux is (2.0+/-0.3) x10^-12 erg cm^-2 s^-1, which is a factor of about 3 higher than that previously observed by Swift/XRT on 2009 February 14,
(7.0+/-2.0) x10^-13 erg cm^-2 s^-1 with Gamma = 1.6+/-0.3.
Swift/UVOT found B3 0650+453 at U= 17.03 +/-0.01 (statistical only). The previous UVOT observation on 2009 February 14 detected the source at U=19.36 +/-0.13. Thus B3 0650+453 is about 2.3 mag brighter in U-band during the recent observations.
Observation of the simultaneous flaring activity in X-ray, UV, optical (ATel #3608) and radio (ATel #3596) bands confirms identification of the flaring GeV source with the blazar B3 0650+453.
We thank the Swift Team, and especially Caryl Gronwall and Craig Swenson, for their rapid scheduling of this observation.
