Very high-energy observations of the Crab nebula with the GRAAL experiment

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dc.creatorArqueros, F.
dc.creatorBallestrin, J.
dc.creatorBerenguel, M.
dc.creatorBorque, D. M.
dc.creatorCamacho, E. F.
dc.creatorDiaz, M.
dc.creatorEnriquez, R.
dc.creatorGebauer, H. -J.
dc.creatorPlaga, R.
dc.date2001-08-06
dc.date.accessioned2026-07-07T01:59:34Z
dc.date.available2026-07-07T01:59:34Z
dc.descriptionThe ``Gamma Ray Astronomy at ALmeria'' (GRAAL) experiment uses 63 heliostat-mirrors with a total mirror area of ~ 2500 m2 from the CESA-1 field to collect Cherenkov light from airshowers. The detector is located in a central solar tower and detects photon-induced showers with an energy threshold of 250 +- 110 GeV and an asymptotic effective detection area of about 15000 m2. Data sets taken in the period September 1999 - September 2000 in the direction of the Crab pulsar were analysed for high energy gamma-ray emission. Evidence for gamma-ray flux from the Crab pulsar with an integral flux of 2.2 +- 0.4 (stat) $^{+1.9}_{-1.5}$ (syst) x 10$^{-9}$ cm$^{-2}$ s$^{-1}$ above threshold and a significance of 4.5 sigma in a total (usable) observing time of 7 hours and 10 minutes on source was found. No evidence for emission from the other sources was seen. The effect of field-of-view restricted to the central part of a detected airshower on the lateral distribution and timing properties of Cherenkov light and their effect on an efficient gamma-hadron separation are discussed.
dc.description4 pages, 3 Postscript figures, to be published in the ICRC 01 proceedings
dc.identifierhttps://arxiv.org/abs/astro-ph/0108092
dc.identifierhttp://arxiv.org/abs/astro-ph/0108092
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/3165
dc.subjectAstrophysics
dc.titleVery high-energy observations of the Crab nebula with the GRAAL experiment
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