スターバースト銀河からガンマ線が検出されました
F Acero1, F Aharonian, A G Akhperjanian
1Laboratoire de Physique Théorique et Astroparticules, Université Montpellier 2, CNRS/IN2P3, CC 70, Place Eugène Bataillon, F-34095 Montpellier Cedex 5, France.
まとめ
星の爆発銀河NGC 253から検出された高エネルギーガンマ線は,宇宙線密度が著しく高いことを示しています. これは,スターバースト銀河が強力な宇宙線工場であり,効率的なエネルギー変換をガンマ線にすることを示唆しています.
科学分野:
- 天体物理学 天体物理学
- 宇宙線物理学 宇宙線物理学
- 高エネルギー天文学 高エネルギー天文学
背景:
- スターバースト銀河は,激しい恒星形成と超新星を体験します.
- 超新星残骸は,宇宙線を高エネルギー (~10^15 eV) に加速させるという説があります.
- ガンマ線は,これらのエネルギッシュな宇宙線のトレーサーとして機能します.
研究 の 目的:
- スターバースト銀河NGC 253からのガンマ線を検出する.
- スターバースト銀河における宇宙線の密度と振る舞いを調査する.
- NGC 253の宇宙線特性を,天の川銀河の特性と比較するために.
主な方法:
- 高エネルギーステレオスコープシステム (H.E.S.S.) を利用しました. アレイ アレイ アレイ アレイ
- ガンマ線検出のために,大気上のチェレンコフ望遠鏡をイメージングに使用した.
- 220億電子ボルト以上のガンマ線流を分析した.
主要な成果:
- NGC 253からの F = (5.5 ± 1.0(stat) ± 2.8(sys)) x 10^-13 cm^-2 s^-1 のガンマ線流が検出されました.
- NGC 253の宇宙線密度は,銀河系の中央のおよそ1000倍であると推論した.
- 観測したところによると,宇宙線エネルギーからガンマ線に変換される割合は,NGC 253では,私たちの銀河に比べて5倍高い.
結論:
- NGC 253のようなスターバースト銀河は,高エネルギー宇宙線の重要な源です.
- 観測されたガンマ線放射は,これらの環境における効率的な宇宙線加速の強力な証拠を提供します.
- NGC 253は,極端な宇宙線物理学の研究のための重要な研究室として機能しています.
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