持続的な無線源に関連した繰り返す高速無線バースト
C-H Niu1, K Aggarwal2,3, D Li4,5,6
1National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China.
Nature
|June 8, 2022
まとめ
FRBは宇宙を研究するのに役立ちます しかし,繰り返されるFRB (20190520B) は,宿主銀河からの高分散量を示し,以前の仮定に異議を唱えます.
科学分野:
- 天体物理学
- 宇宙学
- ラジオ天文学
背景:
- 銀河間媒体のイオン化されたバリオンの含有量を探査するために,高速ラジオバースト (FRB) が利用されます.
- ホスト銀河の分散量 (DM) への貢献は,一般的にマイナーとみなされます.
- 以前の研究では 極端な環境や 恒常的な電波源が FRB の一部に存在すると 指摘されていました
研究 の 目的:
- 繰り返すFRBの検出と位置を報告する, 20190520B
- FRB 20190520Bの宿主銀河の性質と分散測定の貢献を調査する.
- FRB赤偏移の推定に宿主銀河DMの影響を評価する.
主な方法:
- 繰り返し発生するFRB 20190520Bの検出と正確な位置づけ
- コロケーションのコンパクトで永続的な無線源の識別
- 矮星宿主銀河との関連と赤偏移の測定 (0.241 ± 0.001).
主要な成果:
- FRB 20190520Bは 永続的な無線源と共に位置しています
- 宿主銀河は 特定の恒星形成率が高い.
- 異常に高い宿主銀河分散量 (DM ≈ 1.2 × 10^4 pc cm−3) が測定され,銀河間媒体の貢献を大幅に上回った.
結論:
- FRB 20190520Bの宿主銀河DMは,既知のFRB宿主銀河の平均よりほぼ大きさのオーダーです.
- この発見は,すべてのFRBの総分散量で銀河間媒体が優位であるという仮定に異議を唱えます.
- 正確な宿主銀河の識別は,信頼性の高いFRB赤偏移の決定に不可欠です.
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