射手座A*の固有の大きさの検出は,閉じる振幅画像を通して行われました
Geoffrey C Bower1, Heino Falcke, Robeson M Herrnstein
1Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720, USA. gbower@astro.berkeley.edu
まとめ
研究者たちは,我々の銀河の中心にある超大質量ブラックホールである Sagittarius A*の大きさを測定した. この電波放射は,ブラックホールのイベントホライゾンの非常に近くから発生し,その性質に関する新しい洞察を提供します.
科学分野:
- 天体物理学 天体物理学
- ラジオ天文学 ラジオ天文学
背景:
- 射手座A*は,天の川銀河の中心にある超大質量ブラックホールです.
- 超大質量ブラックホールの直接的な環境を理解することは,一般相対性理論と蓄積理論のテストに不可欠です.
研究 の 目的:
- ミリメートルの波長で射手座A*の固有の大きさを決定する.
- 射手座A*のイベント地平線に近い地域を調査する.
主な方法:
- 非常に長いベースライン配列 (VLBA) を利用して高解像度無線観測を行った.
- 7ミリ波長で観測を行った.
主要な成果:
- 射手座A*の固有の大きさは,7ミリ波長で24 +/- 2シュワルツシルト半径と測定されました.
- 1つの観測期間に固有の源の大きさの有意な増加 (60~17~+25) %が検出されました.
- 射手座A*の質量密度の下限を立体天文単位あたり1.4×10^4太陽質量とする.
結論:
- 射手座A*からの短波放射は,イベント地平線に近いところから発生しています.
- 観測された大きさの変動は,ブラックホールの近くの増殖プロセスに関する手がかりを提供することがあります.
- これらの発見は,ブラックホールの物理と環境のモデルを制約する.
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