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軽度の相対論的無線ジェットで,それ以外は正常なタイプIcの超新星2007grから発生した
Z Paragi1, G B Taylor, C Kouveliotou
1Joint Institute for VLBI in Europe (JIVE), Postbus 2, 7990AA Dwingeloo, The Netherlands. zparagi@jive.nl
Nature
|January 30, 2010
まとめ
ラジオ観測により,Ic型超新星SN 2007grの軽度の相対論的膨張が明らかになり,低エネルギージェットであることを示唆しています. この発見は,相対論的なアウトフローが欠如する超新星に関する以前の仮定に異議を唱える.
科学分野:
- 天文学と天体物理学について
- 宇宙の爆発,宇宙の爆発.
- 恒星の進化について
背景:
- Ic型超新星は,長時間続くガンマ線爆発 (GRBs) と関連しており,どちらも巨大な恒星の核の崩壊から生じている.
- GRBは相対論的ジェットを特徴とするが,相対論的アウトフローは,Ic型超新星では決定的に観測されていない.
- 超新星における相対論的アウトフローに関する以前の探求は,無結論でした.
研究 の 目的:
- 型Ic超新星における相対論的アウトフローの存在を調査する.
- ラジオ観測を用いてSN 2007grの膨張特性を特徴づける.
- SN 2007gr.の光学観測と無線観測を一致させるため.
主な方法:
- 60日間の間隔で2つの時代におけるSN 2007grのラジオインターフェロメトリック観測を用いた.
- 放射源の膨張を分析して膨張速度を決定した.
- 電波膨張データを光学観測とスペクトロポリメトリーと比較した.
主要な成果:
- SN 2007grで源の膨張が検出され,0.6cの表面膨張速度の下限が確立されました.
- 光学観測により,典型的なタイプIc超新星噴射速度 (~6,000 km/s) が示され,GRBに関連した超新星よりもはるかに低い.
- 結論は,SN 2007grは,エジェクトの一部から,低エネルギー,軽度相対論的双極無線ジェットを生成し,その大部分は,より遅い,軽度無球形のままである.
結論:
- SN 2007grは軽度の相対論的な膨張の証拠を示し,双極性無線ジェットの存在を示しています.
- SN 2007grのエジェクトの大部分は,典型的な非相対論的速度で膨張した.
- この研究は,Ic型超新星が相対論的な出流を生じさせることができることを示唆しているが,これは潜在的に低エネルギーであり,ラジオ観測と光学観測を調和させる.
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