Spectrum of Very High Energy Gamma-Rays from the blazar 1ES 1959+650 during Flaring Activity in 2002
Abstract
The blazar 1ES 1959+650 was observed in a flaring state with the Whipple 10 m Imaging Atmospheric Cerenkov Telescope in 2002 May. A spectral analysis has been carried out on the data from that time period, and the resulting very high energy gamma-ray spectrum (E>=316 GeV) can be well fitted by a power law of differential spectral index α=2.78+/-0.12stat+/-0.21sys. On 2002 June 4, the source flared dramatically in the gamma-ray range without any coincident increase in the X-ray emission, providing the first unambiguous example of an ``orphan'' gamma-ray flare from a blazar. The gamma-ray spectrum for these data can also be described by a simple power-law fit with α=2.82+/-0.15stat+/-0.30sys. There is no compelling evidence for spectral variability or for any cutoff to the spectrum.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2005
- DOI:
- 10.1086/427406
- arXiv:
- arXiv:astro-ph/0503085
- Bibcode:
- 2005ApJ...621..181D
- Keywords:
-
- Galaxies: BL Lacertae Objects: Individual: Alphanumeric: 1ES 1959+650;
- Gamma Rays: Observations;
- Techniques: Spectroscopic;
- Astrophysics
- E-Print:
- 25 pages. Collaboration website at http://veritas.sao.arizona.edu/