大质量黑洞能限制新星的形成-凯发k8官网

大质量黑洞能限制新星的形成
文章来源:未知 文章作者:enread 发布时间:2014-10-22 07:18 字体: [ ] 
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massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging 1, a study has found. the research provides crucial new evidence that it is these jets of "radio-frequency feedback" streaming from mature galaxies' central black holes that prevent hot free gas from cooling and 2 into baby stars.
 
"when you look into the past history of the universe, you see these galaxies building stars," said tobias marriage, assistant professor of physics and astronomy at johns hopkins and co-lead author of the study. "at some point, they stop forming stars and the question is: why? basically, these active black holes give a reason for why stars stop forming in the universe."
 
the findings have been published in the journal monthly notices of the royal 3 society. they were made possible by adaptation of a well-known research technique for use in solving a new problem.
 
johns hopkins postdoctoral fellow megan gralla found that the sunyaev-zel'dovich effect signature -- typically used to study large 4 clusters -- can also be used to learn a great deal about smaller formations. the sz effect occurs when high-energy electrons in hot gas interact with faint light in the cosmic microwave background, light left over from earliest times when the universe was a thousand times hotter and a billion times 5 than today.
 
"the sz is usually used to study clusters of hundreds of galaxies but the galaxies we're looking for are much smaller and have just a companion or two," gralla said.
 
"what we're doing is asking a different question than what has been 6 asked," gralla said. "we're using a technique that's been around for some time and that researchers have been very successful with, and we're using it to answer a totally different question in a totally different subfield of astronomy."
 
"i was 7 when i saw this paper, because i've never thought that detecting the sz effect from active galactic 8 was possible," said eiichiro komatsu, director of the max planck institute for astrophysics in germany and an expert in the field who was not involved in the research. "i was wrong. … it makes those of us who work on the sz effect from galaxy clusters feel old; research on the sz effect has entered a new era."


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1 fa8833b92b82bcb88ee3b3d7644caf77     
星系( galaxy的名词复数 ); 银河系; 一群(杰出或著名的人物)
参考例句:
  • 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。
2 6becc10b3eacfd79485e188c6ac90cb2     
压扁[平],毁坏,断裂
参考例句:
  • rescuers used props to stop the roof of the tunnel collapsing. 救援人员用支柱防止隧道顶塌陷。
  • the rocks were folded by collapsing into the center of the trough. 岩石由于坍陷进入凹槽的中心而发生褶皱。
3 ketyo     
adj.天文学的,(数字)极大的
参考例句:
  • he was an expert on ancient chinese astronomical literature.他是研究中国古代天文学文献的专家。
  • houses in the village are selling for astronomical prices.乡村的房价正在飙升。
4 ohoxb     
n.星系;银河系;一群(杰出或著名的人物)
参考例句:
  • 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。
5 denser     
adj. 不易看透的, 密集的, 浓厚的, 愚钝的
参考例句:
  • the denser population necessitates closer consolidation both for internal and external action. 住得日益稠密的居民,对内和对外都不得不更紧密地团结起来。 来自英汉非文学 - 家庭、私有制和国家的起源
  • as tito entered the neighbourhood of san martino, he found the throng rather denser. 蒂托走近圣马丁教堂附近一带时,发现人群相当密集。
6 bkzzzc     
adv.以前,先前(地)
参考例句:
  • the bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
7 735ec6d53723be15b1737edd89183ec2     
adj. 震惊的,惊讶的 动词stun的过去式和过去分词
参考例句:
  • the fall stunned me for a moment. 那一下摔得我昏迷了片刻。
  • the leaders of the kopper company were then stunned speechless. 科伯公司的领导们当时被惊得目瞪口呆。
8 thcxf     
n.核
参考例句:
  • to free electrons, something has to make them whirl fast enough to break away from their nuclei. 为了释放电子,必须使电子高速旋转而足以摆脱原子核的束缚。
  • energy is released by the fission of atomic nuclei. 能量是由原子核分裂释放出来的。
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