GRB 990123の光学的な後光の崩壊:火球モデルへの影響
A J Castro-Tirado1, M R Zapatero-Osorio, N Caon
1Instituto de Astrofisica de Andalucia, IAA-CSIC, Granada, Spain. Instituto de Astrofisica de Canarias, La Laguna, Tenerife, Spain. Astronomical Observatory, University of Copenhagen, Copenhagen, Denmark. Nordic Optical Telescope, La Palma, T.
Science (New York, N.Y.)
|March 26, 1999
まとめ
ガンマ線爆発GRB 990123の観測は,光線曲線が順調に減少していることを示しています. 証拠は,コリマートジェットが,イベント後に観察された急激な低下率に責任を負う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
- * 高エネルギー天体物理学
- * 観測宇宙学について
背景:
- * ガンマ線爆発 (GRB) は,宇宙で最も輝く電磁現象です.
- *GRBの放出機構と祖先系を理解することは,天体物理学にとって極めて重要です.
- *GRB 990123は,非常に明るいイベントであり,詳細な研究のためのユニークな機会を提供しました.
研究 の 目的:
- * GRB 990123.3 のブロードバンドの余光を分析するために.
- *GRB 990123の時間およびスペクトルの進化を調査する.
- * 放射モデルを制約し,GRBジェットの性質を調査する.
主な方法:
- * 紫外線から近赤外線までのブロードバンド観測を実施し,事件の8.5時間後に開始.
- * ロボット望遠鏡と一時的な源実験 (ROTSE) とハッブル宇宙望遠鏡 (HST) のデータを活用した.
- * 光の曲線を時間分解率と色の進化について分析した.
主要な成果:
- *GRB 990123.3の余光に平滑に低下する光線が観測されました.
- * 識別された色依存は,イベント後約1日後の紫外線光学帯の冷却中断に関連している可能性があります.
- *1.5〜2日後に急激な低下率が検出され,ジェットコリマーションの兆候です.
結論:
- *GRB 990123の後照光の曲線は,スムーズに膨張している火球からの放射と一致しています.
- * 観測された冷却休憩は,排出機構または粒子冷却の移行を示唆しています.
- * より急激な崩壊は,相対論的,観測者に向かって方向づけられたコリマートジェット構造の方向を指します.
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