<i>FERMI</i> Large Area Telescope Gamma-Ray Detection of the Radio Galaxy M87 [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2009. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- Article numbers 55 : digital, PDF file
- Additional Creators:
- SLAC National Accelerator Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Here, we report the Fermi Large Area Telescope (LAT) discovery of high-energy (MeV/GeV) γ-ray emission positionally consistent with the center of the radio galaxy M87, at a source significance of over 10σ in 10 months of all-sky survey data. Following the detections of Cen A and Per A, this makes M87 the third radio galaxy seen with the LAT. The faint point-like γ-ray source has a >100 MeV flux of 2.45 (±0.63) × 10<sup>–8</sup> photons cm<sup>–2</sup> s<sup>–1</sup> (photon index = 2.26 ± 0.13) with no significant variability detected within the LAT observation. This flux is comparable with the previous EGRET upper limit (<2.18 × 10<sup>–8</sup> photons cm<sup>–2</sup> s<sup>–1</sup>, 2σ), thus there is no evidence for a significant MeV/GeV flare on decade timescales. Contemporaneous Chandra and Very Long Baseline Array data indicate low activity in the unresolved X-ray and radio core relative to previous observations, suggesting M87 is in a quiescent overall level over the first year of Fermi-LAT observations. The LAT γ-ray spectrum is modeled as synchrotron self-Compton (SSC) emission from the electron population producing the radio-to-X-ray emission in the core. The resultant SSC spectrum extrapolates smoothly from the LAT band to the historical-minimum TeV emission. Lastly, alternative models for the core and possible contributions from the kiloparsec-scale jet in M87 are considered, and cannot be excluded.
- Published through SciTech Connect., 11/17/2009., Astrophysical Journal 707 1 ISSN 0004-637X AM, and Abdo, A.; Ackermann, M.; Ajello, M.; Atwood, W.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.; Bloom, E.; Bonamente, E.; Borgland, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T.; Caliandro, G.; Cameron, R.; Cannon, A.; Caraveo, P.; et al.
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