X-Ray/UV/Optical Follow-up of the Blazar PKS 2155-304 after the Giant TeV Flares of 2006 July
Abstract
We present all the publicly available data, from optical/UV wavelengths (UVOT) to X-rays (XRT, BAT), obtained from Swift observations of the blazar PKS 2155-304, performed in response to the rapid alert sent out after the strong TeV activity (up to 17 crab flux level at E>200 GeV) at the end of 2006 July. The X-ray flux increased by a factor of 5 in the 0.3-10 keV energy band and by a factor of 1.5 at optical/UV wavelengths, with roughly 1 day of delay. The comparison of the spectral energy distribution built with data quasi-simultaneous to the TeV detections shows an increase of the overall normalization with respect to archival data but only a small shift of the frequency of the synchrotron peak that remains consistent with the values reported in past observations when the TeV activity was much weaker.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2007
- DOI:
- 10.1086/513271
- arXiv:
- arXiv:astro-ph/0701868
- Bibcode:
- 2007ApJ...657L..81F
- Keywords:
-
- Galaxies: BL Lacertae Objects: General;
- Galaxies: BL Lacertae Objects: Individual: Alphanumeric: PKS 2155-304;
- Astrophysics
- E-Print:
- 13 pages, 3 figures. ApJ Letters, accepted for publication