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arXiv · 1005.0032

Discovery of VHE $\gamma$-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·V. Bugaev·Y. Butt·K. Byrum·A. Cesarini·L. Ciupik·W. Cui·R. Dickherber·C. Duke·J. P. Finley·G. Finnegan·L. Fortson·A. Furniss·N. Galante·D. Gall·G. H. Gillanders·S. Godambe·E. V. Gotthelf·J. Grube·R. Guenette·G. Gyuk·D. Hanna·J. Holder·C. M. Hui·T. B. Humensky·A. Imran·P. Kaaret·N. Karlsson·M. Kertzman·D. Kieda·A. Konopelko·H. Krawczynski·F. Krennrich·M. J. Lang·S. LeBohec·G. Maier·S. McArthur·A. McCann·M. McCutcheon·P. Moriarty·R. Muhkerjee·R. A. Ong·A. N. Otte·D. Pandel·J. S. Perkins·M. Pohl·J. Quinn·K. Ragan·L. C. Reyes·P. T. Reynolds·E. Roache·H. J. Rose·M. Schroedter·G. H. Sembroski·G. Demet Senturk·P. Slane·A. W. Smith·D. Steele·S. P. Swordy·G. Těsić·M. Theiling·S. Thibadeau·V. V. Vassiliev·S. Vincent·S. P. Wakely·J. E. Ward·T. C. Weekes·A. Weinstein·T. Weisgarber·D. A. Williams·S. Wissel·M. Wood·B. Zitzer
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Abstract

We report the discovery of very high energy 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 6.8$\sigma$ and appears point-like given the 5$^{arcminute}$ 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 $\sim$ E$^{-\Gamma}$ with a photon index $\Gamma= 2.39\pm0.23_{stat}\pm0.30_{sys}$. 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 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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V. A. Acciari, E. Aliu, T. Arlen, T. Aune, M. Bautista, M. Beilicke, W. Benbow, D. Boltuch, S. M. Bradbury, J. H. Buckley, V. Bugaev, Y. Butt, K. Byrum, A. Cesarini, L. Ciupik, W. Cui, R. Dickherber, C. Duke, J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, G. H. Gillanders, S. Godambe, E. V. Gotthelf, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, A. Konopelko, H. Krawczynski, F. Krennrich, M. J. Lang, S. LeBohec, G. Maier, S. McArthur, A. McCann, M. McCutcheon, P. Moriarty, R. Muhkerjee, R. A. Ong, A. N. Otte, D. Pandel, J. S. Perkins, M. Pohl, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, M. Schroedter, G. H. Sembroski, G. Demet Senturk, P. Slane, A. W. Smith, D. Steele, S. P. Swordy, G. Těsić, M. Theiling, S. Thibadeau, V. V. Vassiliev, S. Vincent, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, S. Wissel, M. Wood, B. Zitzer. 2010-04-30. Discovery of VHE $\gamma$-ray emission from the SNR G54.1+0.3. https://doi.org/10.1088/2041-8205%2F719%2F1%2Fl69

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