銀河系の中心部から巨大な磁気流出が発生しています
Ettore Carretti1, Roland M Crocker, Lister Staveley-Smith
1CSIRO Astronomy and Space Science, PO Box 276, Parkes, New South Wales 2870, Australia. Ettore.Carretti@csiro.au
Nature
|January 4, 2013
まとめ
銀河系近くで発見された巨大なラジオロブ.
科学分野:
- 天体物理学 天体物理学
- 銀河系天文学 銀河系天文学
- プラズマ物理学 プラズマ物理学
背景:
- 銀河系の中核には,激しい恒星形成と超大質量ブラックホールがある.
- 謎めいたガンマ線を放射する構造である『フェルミ・バブル』は,銀河の中心の上と下に広がっています.
- フェルミバブルの起源 (恒星形成とブラックホールの活動) とその磁場は不明のままである.
研究 の 目的:
- フェルミ・バブルの起源を調査する.
- これらの銀河の外流内の磁場構造を特徴づける.
- 銀河の中心で観測された現象の背後にある駆動機構を決定する.
主な方法:
- 銀河中心からの偏光放射のラジオ観測.
- ラジオロブの範囲と構造をマッピングする.
- 磁場強度とロブ内の向きの分析.
主要な成果:
- 銀河の中心から約60度まで広がる2つの巨大で,線形に偏ったラジオロブを発見した.
- ラジオロブ内の3つの脊状の基礎構造の識別.
- 強い磁場 (最大15マイクロガウス) がロブに浸透し,フェルミ・バブル構造と密接に一致する検出.
結論:
- ラジオロブは,ブラックホールの活動ではなく,星形成によって引き起こされる二角形の流出の証拠です.
- この流出は,銀河のハローに相当な磁気エネルギー (~10^55エルグ) を運ぶ.
- 内側の山脊は,何百万年にもわたる核星の形成の歴史を記録しているのかもしれない.
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