GRB 060614からの新しいガンマ線爆発分類スキーム
N Gehrels1, J P Norris, S D Barthelmy
1NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. gehrels@milkyway.gsfc.nasa.gov
Nature
|December 22, 2006
まとめ
近くのガンマ線爆発 (GRB) は,既存の分類に異議を唱えている. この長期間続くイベントには超新星が欠けていたため,新しいGRBカテゴリが必要になる可能性があることを示唆しています.
科学分野:
- 天体物理学 天体物理学
- 宇宙の爆発,宇宙の爆発.
- ガンマ線天文学のガンマ線天文学
背景:
- ガンマ線爆発 (GRBs) は,その放射の持続時間に基づいて,異なる起源と関連する現象を持つ長時間および短時間タイプに分類されます.
- 長期にわたるGRBは,通常,恒星形成地域における大規模な恒星崩壊 (コラプサール) と関連しており,しばしば超新星とともに発生します.
- 短期間のGRBは,より活動的でない銀河の領域におけるコンパクトな物体の融合 (中性子星-中性子星または中性子星-ブラックホール) と関連しており,通常は超新星がない.
研究 の 目的:
- 特殊なガンマ線爆発GRB 060614.4の性質を調査する.
- GRB 060614が,既定の長いまたは短いGRB分類に適合するかどうかを判断する.
- GRB 060614の性質が現在のGRB形成モデルに与える影響を調査する.
主な方法:
- GRB 060614の持続時間,タイムラグ,ピーク明るさの分析.
- 付随する超新星を探すために,深い光学観測を行う.
- GRB 060614の特徴と,既知の長短GRBの特徴を比較する.
主要な成果:
- GRB 060614は,長時間GRBと並行して,約102秒の持続時間を示しました.
- その一時的な遅延とピークの明るさは,短時間のGRBの特徴でした.
- 深い光学観測は,付随する超新星の存在を決定的に排除した.
結論:
- GRB 060614は,長い期間と超新星の欠如のユニークな組み合わせを提示し,既存のGRB分類スキームに挑戦しています.
- この発見は,現在存在するクララサールやコンパクトオブジェクトの融合に関するモデルは,観測されたすべてのGRB現象を完全に説明できないことを示唆している.
- この出来事は,GRBの起源を再評価し,長短GRBを橋渡しする新しい分類の導入を可能とする.
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