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发信人: 2sinxcosx(2sinxcosx) 整理人: 2sinxcosx(2003-02-17 01:04:40), 站内信件 |
点击这里查看完整大图 美捕捉到人马座A星系大爆炸奇观 (2002年08月14日 21:43 大洋论坛) 天文学家根据目前的发现推测，大约一千万年前，人马座A银河经历了一次巨大的爆炸。 大洋网讯 美国东部时间8月13日(北京时间8月14日)消息，美国国家宇航局利用多种天文探测手段捕捉到了位于人马座A的一个银河星系大爆发时的情景，这个天文奇观不仅让地球上的人们大饱眼福，同时还对天文学家研究巨型黑洞形成的机制以及银河星系之间的相互关系提供了重要的参考依据。 美国国家宇航局利用钱德拉X光轨道天文台、哈勃天文望远镜和新墨西哥州的巨型阵列望远镜捕捉到了位于人马座A的一个银河星系大爆发时的奇观。科学家们将这个星系爆发时产生的无线电波喷发用红色和绿色描绘，将可见光用黄色和橙色描绘，将X光用蓝色描绘，从而比较完整地勾勒出了这个星系爆发时的美妙场景。据悉，人马座A银河星系数百万年前曾发生过一次大爆发，人们现在看到的奇观就是那次爆炸时的情景。 NASA的观测显示，人马座A银河星系中有两个直径超过25000光年的巨型“尘埃环”，其内部温度估计高达数百万度。此外，该银河星系还有两个喷射出高能粒子的暗流，它们的能量源于银河中心部位的一个超级巨型黑洞。天文学家根据目前的发现推测，大约一千万年前，人马座A银河经历了一次巨大的爆炸。另有天文学家认为，这个银河可能在一亿年前吞噬了一个小型银河。将于9月6日出版的美国《天体物理学》期刊将刊登一篇有关人马座银河星系的研究论文，这篇论文由美国天文学家马加里塔-卡罗夫斯卡(Margarita Karovska)主笔，论文的主要内容即是研究人马座银河星系。 ---------------------------------------------------------------------- Centaurus A Arcs: Arcs Tell The Tale Of A Giant Eruption Credits: X-ray (NASA/CXC/M. Karovska et al.); Radio 21-cm image (NRAO/VLA/Schiminovich, et al.), Radio continuum image (NRAO/VLA/J.Condon et al.); Optical (Digitized Sky Survey U.K. Schmidt Image/STScI) JPEG (304 k), Tiff (5.1 MB), PS (6.9 MB) A composite X-ray (blue), radio (pink and green), and optical (orange and yellow) image of the galaxy Centaurus A presents a stunning tableau of a galaxy in turmoil. A broad band of dust and cold gas is bisected at an angle by opposing jets of high-energy particles blasting away from the supermassive black hole in the nucleus. Two large arcs of X-ray emitting hot gas were discovered in the outskirts of the galaxy on a plane perpendicular to the jets. The arcs of multimillion degree gas appear to be part of a projected ring 25,000 light years in diameter. The size and location of the ring indicate that it may have been produced in a titanic explosion that occurred about ten million years ago. Such an explosion would have produced the high-energy jets, and a galaxy-sized shock wave moving outward at speeds of a million miles per hour. The age of 10 million years for the outburst is consistent with optical and infrared observations that indicate that the rate of star formation in the galaxy increased dramatically at about that time. Scientists have suggested that all this activity may have begun with the merger of a small spiral galaxy and Centaurus A about 100 million years ago. Such a merger could eventually trigger both the burst of star formation and the violent activity in the nucleus of the galaxy. The tremendous energy released when a galaxy becomes "active" can have a profound influence on the subsequent evolution of the galaxy and its neighbors. The mass of the central black hole can increase, the gas reservoir for the next generation of stars can be expelled, and the space between the galaxies can be enriched with heavier elements. Fast Facts for Centaurus A Arcs: Credit X-ray (NASA/CXC/M. Karovska et al.); Radio 21-cm image (NRAO/VLA/Schiminovich, et al.), Radio continuum image (NRAO/VLA/J. Condon et al.); Optical (Digitized Sky Survey U.K. Schmidt Image/STScI) Scale Images are about 18 x 17 arcmin Category Quasars & Active Galaxies Coordinates (J2000) RA 13h 25m 28s | Dec -43º 01' 11" Constellation Centaurus Observation Date HRC-I: September 10, 1999 Observation Time HRC-I: 4.7 hours Obs. ID HRC-I: 463 Color Code X-ray (blue); optical (yellow-orange); radio (green and pink). Instrument HRC Distance Estimate 11 million light years ---- 欢迎来“宇宙探索”论坛^-^---->探索宇宙 ～ 超越无限 ～ ！ |
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