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DISCOVERY OF VERY HIGH ENERGY γ-RAY EMISSION FROM THE SNR G54.1+0.3
Journal article   Open access   Peer reviewed

DISCOVERY OF VERY HIGH ENERGY γ-RAY EMISSION FROM THE SNR G54.1+0.3

V. A Acciari, E Aliu, T Arlen, T Aune, M Bautista, M Beilicke, W Benbow, D Boltuch, S. M Bradbury, J. H Buckley, …
Astrophysical journal. Letters, Vol.719(1), pp.L69-L73
08/10/2010
DOI: 10.1088/2041-8205/719/1/L69
url
https://doi.org/10.1088/2041-8205/719/1/L69View
Published (Version of record) Open Access

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.

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