加载中…巨型星系年龄越大胃口越差
(2013-08-08 11:13:06)
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杂谈 |
分类： 科学与技术 |
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利用美国航空航天局两架太空望远镜获得的数据所做的最新研究表明，与以前的理论相反，位于星团中心的巨型星系的增长速度似乎随时间的推移而放缓，吞噬的邻近星系也越来越少。
宇宙间充满了大小不同的星系群，在重力的作用下聚集成更大的群体，被称为星团。大多数的星团中心都有一个巨型星系，一般认为巨型星系会通过与邻近的星系合并不断壮大。天文学家称这个过程为星系吞噬。
但美国航空航天局（NASA）的史匹哲太空望远镜（Spitzer Space Telescope）和广域红外线巡天探测卫星（Wide-field Infrared Survey Explorer）最新的观察结果与此前的理论相反，这些巨型星系的增长似乎随时间的推移逐渐放缓，吞噬的邻近星系也越来越少。
这张图片显示的是由广域红外线巡天探测卫星（左侧）和斯皮策太空望远镜（右侧）观测到的两个星团。每张图中心部位就是处于每一个星团中央的最大星系。
《天体物理学刊》（Astrophysical Journal）发表了一项研究报告。据研究报告的主要作者，台湾台北的中央研究院（Academia Sinica）研究人员林彦廷说，“我们发现这些巨大星系在近50亿年以来似乎开始节食，食量变少，质量的增长停下来。”
这项新发现将有助于研究人员了解星团——宇宙中最巨大的结构之一——是如何形成和演变的。
关于星团研究的详情见美国航空航天局新闻稿
Read more: http://iipdigital.usembassy.gov/st/chinese/inbrief/2013/08/20130807280175.html#ixzz2bLNEbBjO
Monster Galaxies Lose Their Appetite with Age
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New research using data from two of NASA’s space telescopes is showing that, contrary to previous theories, the gargantuan galaxies at the center of galaxy clusters appear to slow their growth over time, feeding less and less off their neighboring galaxies.
The universe is filled with gobs of galaxies, bound together by gravity into larger families called clusters. Lying at the heart of most clusters is a monster galaxy thought to grow in size by merging with neighboring galaxies, a process astronomers call galactic cannibalism.
New research from NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) is showing that, contrary to previous theories, these gargantuan galaxies appear to slow their growth over time, feeding less and less off neighboring galaxies.
This image shows two of the galaxy clusters observed by WISE (left) and Spitzer (right). The central and largest galaxy in each grouping is seen at the center of each image.
“We’ve found that these massive galaxies may have started a diet in the last 5 billion years, and therefore have not gained much weight lately,” said Yen-Ting Lin of the Academia Sinica in Taipei, Taiwan, lead author of a study published in the Astrophysical Journal.
The new findings will help researchers understand how galaxy clusters — among the most massive structures in the universe — form and evolve.
For more on the research into galaxy clusters, see the NASA press release.
Read more: http://iipdigital.usembassy.gov/st/english/inbrief/2013/08/20130805280069.html#ixzz2bLNGUsvK
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