{ "id": "1410.5208", "version": "v1", "published": "2014-10-20T09:49:41.000Z", "updated": "2014-10-20T09:49:41.000Z", "title": "Fermi-LAT Detection of Pulsed Gamma-rays Above 50 GeV from the Vela Pulsar", "authors": [ "Gene C. K. Leung", "J. Takata", "C. W. Ng", "A. K. H Kong", "P. H. T. Tam", "C. Y. Hui", "K. S. Cheng" ], "comment": "14 pages, 4figures, accepted by ApJ Letter", "categories": [ "astro-ph.HE" ], "abstract": "The First \\fermi-LAT Catalog of Sources Above 10 GeV reported evidence of pulsed emission above 25 GeV from 12 pulsars, including the Vela pulsar, which showed evidence of pulsation at $>37$ GeV energy bands. Using 62 months of \\fermi-LAT data, we analyzed the gamma-ray emission from the Vela pulsar and searched for pulsed emission above 50 GeV. Having confirmed the significance of the pulsation in 30-50 GeV with the H-test (p-value $\\sim10^{-77}$), we extracted its pulse profile using the Bayesian block algorithm and compared it with the distribution of the 5 observed photons above 50 GeV using the likelihood ratio test. Pulsation was significantly detected for photons above 50 GeV with p-value $=3\\times10^{-5}$ ($4.2\\sigma$). The detection of pulsation is significant above $4\\sigma$ at $>79$ GeV and above $3\\sigma$ at $>90$ GeV energy bands, making this the highest energy pulsation significantly detected by the LAT. We explore non-stationary outer gap scenario of the very high-energy emissions from the Vela pulsar.", "revisions": [ { "version": "v1", "updated": "2014-10-20T09:49:41.000Z" } ], "analyses": { "keywords": [ "vela pulsar", "fermi-lat detection", "pulsed gamma-rays", "gev energy bands", "energy pulsation" ], "tags": [ "journal article" ], "publication": { "doi": "10.1088/2041-8205/797/2/L13", "journal": "The Astrophysical Journal", "year": 2014, "month": "Dec", "volume": 797, "number": 2 }, "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable", "inspire": 1322892, "adsabs": "2014ApJ...797L..13L" } } }