{"paper":{"title":"Observation of gamma-rays greater than 10 TeV from Markarian 421","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"A. Asahara, A. Kawachi, A. Maeshiro, A. Watanabe, C. Itoh, D.L. Swaby, F. Kajino, F. Tokanai, G.V. Bicknell, H. Katagiri, H. Kubo, H. Muraishi, H. Tsunoo, J. Kataoka, J. Kushida, J.R. Patterson, K. Nishijima, K. Okumura, K. Sakurazawa, K. Takano, K. Tsuchiya, K. Uruma, M. Mori, M. Moriya, M. Ohishi, P.G. Edwards, R. Enomoto, R. Suzuki, S. Gunji, S. Hara, S. Hayashi, S. Kabuki, S. Maeda, S. Yanagita, T. Hara, T. Kifune, T. Naito, T. Nakase, T. Takano, T. Tanimori, T. Yoshida, T. Yoshikoshi, Y. Matsubara, Y. Mizumoto, Y. Muraki","submitted_at":"2002-09-24T02:52:06Z","abstract_excerpt":"We have observed Markarian 421 in January and March 2001 with the CANGAROO-II imaging Cherenkov telescope during an extraordinarily high state at TeV energies. From 14 hours observations at very large zenith angles, $\\sim70^\\circ$, a signal of 298 $\\pm$ 52 gamma-ray--like events (5.7 $\\sigma$) was detected at $E>10$ TeV, where a higher sensitivity is achieved than those of usual observations near the zenith, owing to a greatly increased collecting area. Under the assumption of an intrinsic power-law spectrum, we derived a differential energy spectrum $dN/dE =\n  (3.3 \\pm 0.9_{stat.} \\pm 0.3_{sy"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/0209487","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/astro-ph/0209487/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}