近隣のブラックホールバイナリV404 Cygniの急速な光学変化の繰り返しパターン
Mariko Kimura1, Keisuke Isogai1, Taichi Kato1
1Department of Astronomy, Graduate School of Science, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
Nature
|January 8, 2016
まとめ
天体物理学者は 長い軌道周期だけでなく 高度な蓄積率も V404 Cygniのようなブラックホールシステムで 大幅の光学振動を誘発することを発見しました これは,蓄積円盤の不安定性に関する以前の理論に異議を唱える.
科学分野:
- 天体物理学
- ブラックホールの研究
- アクレションディスクダイナミクス
背景:
- ブラックホールの蓄積メカニズムは 十分に理解されていません
- 収縮円盤は,特にエディントン限界の近くで,X線の変動を引き起こすと考えられています.
- 前回の観測では 大幅の振動が 高質量増加率と関連していた.
研究 の 目的:
- ブラックホール系における 大幅の光学振動の原因を調査する
- 内部ディスクの不安定性を誘発するための重要なパラメータを決定する.
- 質量増加率と他の要因の役割を再評価する.
主な方法:
- V404 Cygniの多色光学データ分析について
- 観測された振動と質量増加率と軌道周期の比較.
- バイナリシステムにおける蓄積円盤の理論モデル化.
主要な成果:
- 100秒から2.5時間の時間スケールで観測された大幅の光学振動.
- これらの振動は,以前に想定されたより大幅に低い質量増加率で発生した.
- これらの振動の重要な条件として,長い軌道周期が特定されました.
結論:
- 内部円盤の不安定性に対する唯一の重要なパラメータは 質量増加率ではありません
- 外部円盤の表面密度が低いため 長い軌道周期が不可欠です
- 長期系におけるこれらの振動は,速度そのものよりも持続的な増殖の欠如が原因である.
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