検出されたガンマ線爆発のない相対論型Ibc超新星
A M Soderberg1, S Chakraborti, G Pignata
1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, Massachusetts 02138, USA. asoderberg@cfa.harvard.edu
Nature
|January 30, 2010
まとめ
科学者たちは超新星SN 2009bbから発光した放射能を発見し,中央エンジンからの強力な流出を示した. これは,超新星における相対論的アウトフローを探すことによって,隠れたガンマ線爆発 (GRBs) を発見するための新しい方法を示唆しています.
科学分野:
- 天体物理学 天体物理学
- 宇宙の爆発,宇宙の爆発.
- 超新星とガンマ線爆発
背景:
- 長期にわたるガンマ線爆発 (GRB) は,巨大な星の爆発的な死と関連しており,タイプIbc超新星の一種である珍しいサブクラスを形成しています.
- これらのイベントは,中央エンジン (ブラックホールまたは中性子星) から相対論的な流出が特徴であり,ガンマ線パルスとラジオ後光として観察されます.
- 多くのGRBは,計器の感度制限や地球から遠ざかる放射により検出されない可能性があります.
研究 の 目的:
- 相対論的なアウトフローを持つ超新星のためのラジオ検索を通じて,以前に発見されなかったGRBを検出する可能性を調査する.
- ガンマ線検出を超えた中央エンジン活動の特徴を示す超新星を特定する.
主な方法:
- タイプIbc超新星に関する無線調査が行われました.
- SN 2009bbからの光放射の分析により,相対論的出流の存在を推測した.
- GRBの発生率と超新星集団に関する既存のデータとの発見の比較.
主要な成果:
- タイプIbcの超新星SN 2009bbから発光放射が検出され,中央エンジンで駆動された実質的な相対論的流出を示しています.
- この研究では,Ibc型超新星の約"%に中央エンジンが搭載されていると推定されており,これは独立したGRB発生率の推定と一致しています.
- 2つ目の,軽度の相対論的超新星も独立して特定されました.
結論:
- ラジオ観測は,超新星における相対論的アウトフローを検出することによって,隠されたガンマ線爆発 (GRB) 集団を明らかにすることができます.
- 超新星SN 2009bbは,以前に分類されていないイベントで,中央エンジン活動の証拠を提供します.
- 超新星における中央エンジンの発生率は低いが,観測されたGRBの発生率と一致しており,検出されていないGRBの有意な集団があることを示唆しています.
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