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- Fermi-LAT discovery of GeV gamma-ray emission from the young supernova remnant Cassiopeia A doi link

Author(s): A. Abdo A., Ackermann M., Ajello M., Allafort A., Baldini L., Ballet J., Barbiellini G., G. Baring M., Bastieri D., M. Baughman B., Bruel P., M. Casandjian J., Cohen-Tanugi J., Dumora D., Farnier C., J. Fegan S., Fortin P., Grondin M.-H., Guillemot L., Horan D., Knödlseder J., Lemoine-Goumard M., Lott B., Nuss E., Pelassa V., Piron F., Reposeur T., A. Smith D., Tibaldo L., Vilchez N.

(Article) Published: The Astrophysical Journal / The Astrophysical Journal Letters, vol. 710 p.L92-L97 (2010)
Links openAccess full text : arxiv


Ref HAL: in2p3-00461069_v1
Ref Arxiv: 1001.1419
DOI: 10.1088/2041-8205/710/1/L92
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
136 citations
Abstract:

We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2$\sigma$ above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as $W_{\mathrm{CR}} \approx (1-4) \times 10^{49}$ erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B $\gt 0.1$ mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.