[译文] 有色类星体暗示宇宙是“烟雾缭绕的”
本帖最后由 deepgreen 于 2009-3-5 12:21 编辑原文：http://www.astronomynow.com/090227SmokyUniverse.html
Coloured quasars suggest ‘smoky’ Universe
有色类星体暗示宇宙是“烟雾缭绕的”
Hold your breath: we may be living in a smoky Universe that dims light from distant objects such as quasars, or so say astronomers working on the Sloan Digital Sky Survey (SDSS).
别惊讶：我们可能生活在一个烟雾缭绕的宇宙，来自类星体之类遥远天体的光是被削弱过的。这是正在进行斯隆数字巡天(SDSS)的天文学家们的说法。
Just like when a sunset appears reddened because it has to travel through more of Earth’s atmosphere, light from quasars could appear redder because it has to travel through the dust of intervening galaxies. “Galaxies contain lots of dust, most of it formed in the outer regions of dying stars,” says study team leader Dr Brice Menard of the Canadian Institute for Theoretical Astrophysics. “The surprise is that we are seeing dust hundreds of thousands of light years outside of the galaxies – in intergalactic space.” The team’s findings have been published in the Monthly Notices of the Royal Astronomical Society.
恰似夕阳看起来变红了是因为那时阳光要穿过更多的地球大气,来自类星体的光也可能因为需要穿越途中的星际尘埃而显得更红。“星系中存在大量尘埃，其中绝大部分形成于垂死恒星的外围区域，”加拿大理论天体物理中心的研究组组长Brice Menard博士说道。“意外的是我们在距离星系数十万光年的星系际空间观察到了尘埃。”这个研究组的发现已被刊发在皇家天文学会月报。
Using images from SDSS 2, the team analyzed 100,000 distant quasars, which were located behind at least 20 million galaxies. “Putting together and analyzing this huge dataset required cutting-edge ideas from computer science and statistics,” says team member Gordon Richards of Drexel University. “Averaging over so many objects allowed us to measure an effect that is much too small to see in any individual quasar.”
基于SDSS 2的图像，该研究组分析了10万个远距离类星体，它们和地球之间有着至少2千万个星系。“将如此多的信息汇集起来，并对所得到的巨型数据集作分析，需要来自计算机科学和统计学的一流理念，”研究组成员之一，卓克索大学的Gordon Richards说道。“将如此之多天体的信息加以平均，使我们得以量度对于单颗类星体而言太过微小的效应。”
Why could this ‘haze’ be filling the Universe instead of remaining in its galactic confines? There are two theories. In one, supernovae explosions and strong winds from massive stars push gas and dust out of galaxies. In the other theory, this process occurs by radiation pressure on the dust by starlight. “Our findings now provide a reference point for theoretical studies,” says Menard.
为什么这样的“雾霭”会充斥宇宙而不是呆在相应的星系(引力?)所限的范围之内呢？有两个理论可以解释。其中一个认为，超新星爆炸以及大质量恒星的恒星风把气体和尘埃推出了星系。另一理论则认为，该现象缘于星光作用于尘埃的辐射压。“我们的发现为理论研究提供了一个参考点，”Menard说道。
Whatever the mechanism that drives dust out into intergalactic space, its presence there could be a problem. Cosmological observations that make use of distant quasars and supernovae to gauge the size and age of the Universe, as well as the presence of the mysterious ‘dark energy’ (thought to be responsible for the expansion of the Universe) could be affected. However, Menard says that the presence of dust doesn’t remove the need for dark energy and that any estimates would merely have to account for the dust. He adds, “These experiments are very ambitious in their goals and subtle effects matter.”
不论是哪种机制把尘埃赶到星系际空间，它们在那里的存在可能引发问题。通过遥远的类星体和超新星来测量宇宙的大小和年龄的天文观测，以及神秘的“暗能量”的存在（被认为是宇宙膨胀的原因）都可能受到影响。但是，Menard说星系际尘埃的存在并不意味着不需要暗能量了，任何估测只需要把星系际尘埃这个因素考虑在内即可。他补充道,“这些实验就其目标而言雄心勃勃，但是对实际问题的影响则是比较细微的。” 今天批量生产啊？ 小批量。。。因为文章很短。
算是抛砖引玉吧，开新版了，希望有更多新文章啊。 ::070821_10.jpg::原来还有一篇啊~~大叔的效率很高啊 3# deepgreen
尘埃充斥的宇宙会不会影响光谱学的研究呢？
shn_117 发表于 2009-3-3 11:20 http://www.astronomy.com.cn/bbs/images/common/back.gif
现在的光谱学应该早已考虑到星系际尘埃的影响了。。。比如类星体的D型吸收线（Ly-Alpha线丛）就被认为很可能是星系际介质造成的。不知SDSS的研究中是不是用到了光谱学的手段？ 6# shn_117
这样叫比较顺口呀::07:: 5# 一分半
我发现一个奇怪的问题~~
你为什么老叫他“大叔”呢？？
shn_117 发表于 2009-3-3 11:19 http://www.astronomy.com.cn/bbs/images/common/back.gif
这个可有些历史渊源了。。。正电子和我曾经通过抗争成功摆脱了“您老”的称号，至于这个就当ID之类的看待，并无特别含义就好了。。。 ::06::大叔把陈年旧帐都翻出来了~~
话说~~这些星际尘埃为什么没有像其他星系那样结合到一起呢？是因为数量不够，没有足够的引力？ 13# 一分半
依我看可能是因为没有形成质量中心，这样就很难聚集了。
shn_117 发表于 2009-3-4 08:27 http://www.astronomy.com.cn/bbs/images/common/back.gif
我觉着啊，没有形成质量中心原因之一可能还是数量不够，没有形成足够的引力。。。
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