Discovery of Very High Energy γ-ray Emission from the SNR G54.1+0.3
Abstract
We report the discovery of very high energy (VHE) gamma-ray emission from the direction of the SNR G54.1+0.3 using the VERITAS ground-based gamma-ray observatory. The TeV signal has an overall significance of 6.8σ and appears pointlike given the resolution of the instrument. The integral flux above 1 TeV is 2.5% of the Crab Nebula flux and significant emission is measured between 250 GeV and 4 TeV, well described by a power-law energy spectrum dN/dE ~ E -Γ with a photon index Γ = 2.39 ± 0.23stat ± 0.30sys. We find no evidence of time variability among observations spanning almost two years. Based on the location, the morphology, the measured spectrum, the lack of variability, and a comparison with similar systems previously detected in the TeV band, the most likely counterpart of this new VHE gamma-ray source is the pulsar wind nebula (PWN) in the SNR G54.1+0.3. The measured X-ray to VHE gamma-ray luminosity ratio is the lowest among all the nebulae supposedly driven by young rotation-powered pulsars, which could indicate a particle-dominated PWN.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2010
- DOI:
- 10.1088/2041-8205/719/1/L69
- arXiv:
- arXiv:1005.0032
- Bibcode:
- 2010ApJ...719L..69A
- Keywords:
-
- gamma rays: general;
- ISM: supernova remnants;
- pulsars: individual: J1930+1852 J1928+1746;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 5 pages, 2 figure, Latex, emulateapj style, accepted by the Astrophysical Journal Letters