文章来源:未知 文章作者:meng 发布时间:2010-05-13 03:11 字体: [ ]  进入论坛

A team of astronomers1(天文学家) including Ivelina Momcheva of the Carnegie Observatories2 has discovered the most distant cluster of galaxies3 ever found. In a surprising twist, the young cluster born just 2.8 billion years after the Big Bang appears remarkably4 similar to the much older present-day galaxy5 clusters. "We were looking for clusters of galaxies when the Universe was still very young," says Carnegie's Momcheva, who did the spectroscopic analysis(光谱分析) which led to the discovery of the cluster. "One might think that the clusters we find would look young as well. However in this cluster we found a number of surprisingly ancient-looking galaxies. This cluster resembles modern-day clusters, which are nearly 10 billion years older."

"It is like we dug an archeological(考古学的) site in Rome and found pieces of modern Rome in amongst the ruins," adds lead author Casey Papovich of Texas A&M University.

CLG J02182-05102, as the cluster is called, contains approximately(大约,近似) 60 galaxies, including several enormous red galaxies at its center holding 10 times as many stars as the Milky6 Way(银河) . Such galaxies were thought to be rare in the universe at this early stage. Similar galaxy clusters today have had billions of more years to develop and grow.

The cluster was first detected using NASA's Spitzer Space Telescope, which is sensitive to the infrared7 light(红外光) emitted by the galaxies. The researchers observed the high density8 of galaxies within CLG J02182-05102, but could not determine from the Spitzer data whether its galaxies are indeed gravitationally bound, as is the case with true galaxy clusters. For these measurements, they used an advanced spectrograph(光谱仪) on the Carnegie Institution's Magellan/Baade 6.5 meter telescope at the Las Campanas Observatory9 in Chile. Analyzing10 the faint light from seven galaxies near the center the cluster, they found that the galaxies had an average redshift of 1.62. "This means that we are seeing it the way it looked 9.6 billion years ago," says Momcheva. "Since then it has moved away from us as the universe has expanded. Today the distance to the cluster is 15 billion light years."

Galaxy clusters are the largest gravitationally bound structures in the Universe, and studying the new discovery will help researchers understand how galaxies evolve and form clusters. CLG J02182-05102's large red galaxies are unexpected because most galaxies at that time were still rapidly forming stars, and, as a result, appear smaller and their emitted light bluer.

For the galaxies in ClG J02182-05102 to have become chock full(塞满了的) of old, red stars so quickly compared to their contemporaries(同辈,同龄人) , these galaxies must have "lived fast and died young," Papovich said.

"We are witnessing the youth of truly massive cluster of galaxies," says Momcheva. "ClG J02182-05102 will continue growing, accreting11 more galaxies and slowly aging. By the present day it has probably grown to be a large metropolis12 of a cluster like our neighbor, the Coma13 cluster."


1 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者,天文学家( astronomer的名词复数 )
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪,为什么只有土星有光环。 来自《简明英汉词典》
2 observatories d730b278442c711432218e89314e2a09     
n.天文台,气象台( observatory的名词复数 )
  • John Heilbron, The Sun in the Church: Cathedrals as Solar Observatories, 3-23. 约翰.海耳布隆,《教会里的太阳:教堂即太阳观测台》,第3-23页。 来自互联网
  • Meteorologists use satellites, land observatories and historical data to provide information about the weather. 气象学家使用卫星、上天文台和历史资料来提供有关天气的信息。 来自互联网
3 galaxies fa8833b92b82bcb88ee3b3d7644caf77     
星系( galaxy的名词复数 ); 银河系; 一群(杰出或著名的人物)
  • Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
  • We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。
4 remarkably EkPzTW     
  • I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
  • He made a remarkably swift recovery. 他康复得相当快。
5 galaxy OhoxB     
  • The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
  • The company has a galaxy of talent.该公司拥有一批优秀的人才。
6 milky JD0xg     
  • Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
  • I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。
7 infrared dx0yp     
  • Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
8 density rOdzZ     
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
9 observatory hRgzP     
  • Guy's house was close to the observatory.盖伊的房子离天文台很近。
  • Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
10 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析;分析( analyze的现在分词 );分解;解释;对…进行心理分析n.分析
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据,暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然,他对其预测所作的分析倒也八九不离十。 来自辞典例句
11 accreting f86865665bd26596fdf1bff752bfc00a     
v.共生( accrete的现在分词 );合生;使依附;使连接
  • Accreting to statistic, 75 percent of students'school time is spent in the class. " 据统计,学生在学校的活动总量有75%的时间是在课堂上度过的。 来自互联网
12 metropolis BCOxY     
  • Shanghai is a metropolis in China.上海是中国的大都市。
  • He was dazzled by the gaiety and splendour of the metropolis.大都市的花花世界使他感到眼花缭乱。
13 coma vqxzR     
  • The patient rallied from the coma.病人从昏迷中苏醒过来。
  • She went into a coma after swallowing a whole bottle of sleeping pills.她吃了一整瓶安眠药后就昏迷过去了。
TAG标签: stars cluster galaxies