Hard X-ray emission clumps in the γ-Cygni supernova remnant: An INTEGRAL-ISGRI view
Abstract
Spatially resolved images of the galactic supernova remnant G78.2+2.1 (γ-Cygni) in hard X-ray energy bands from 25 keV to 120 keV are obtained with the IBIS-ISGRI imager aboard the International Gamma-Ray Astrophysics Laboratory INTEGRAL. The images are dominated by localized clumps of about ten arcmin in size. The flux of the most prominent North-Western (NW) clump is (1.7±0.4)×10-11 erg cm-2 s-1 in the 25-40 keV band. The observed X-ray fluxes are in agreement with extrapolations of soft X-ray imaging observations of γ-Cyg by ASCA GIS and spatially unresolved RXTE PCA data. The positions of the hard X-ray clumps correlate with bright patches of optical line emission, possibly indicating the presence of radiative shock waves in a shocked cloud. The observed spatial structure and spectra are consistent with model predictions of hard X-ray emission from nonthermal electrons accelerated by a radiative shock in a supernova interacting with an interstellar cloud, but the powerful stellar wind of the O9V star HD 193322 is a plausible candidate for the NW source as well.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 2004
- DOI:
- 10.1051/0004-6361:200400089
- arXiv:
- arXiv:astro-ph/0410688
- Bibcode:
- 2004A&A...427L..21B
- Keywords:
-
- gamma rays: observations;
- X rays: ISM: supernova remnants;
- individual: G78.2+2.1 (γ-Cygni);
- radiation mechanisms: nonthermal;
- cosmic rays;
- Astrophysics
- E-Print:
- 5 pages, 5 figures, Astronomy and Astrophysics Letters