APOD090702 Lyman-α氢云团

今天的APOD图是多个望远镜照片的合成，应该在钱德拉X线卫星的主页有其更详细的介绍。好了，让我们来看图
http://apod.nasa.gov/apod/ap090702.html

2009 July 2
Lyman Alpha Blob

                               
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Credit: NASA / ESA, CXC, JPL-Caltech, STScI, NAOJ, J.E. Geach (Univ. Durham) et al.
Illustration: NASA/CXC/M.Weiss
Explanation:
Dubbed a Lyman-alpha blob, an enormous cloud of hydrogen gas spans several hundred thousand light-years in this remarkable image (left), a composite of x-ray, optical, and infrared data from space and ground based observatories. The gigantic, amoeba-like structure is seen as it was when the universe was a mere 2 billion years old (about 12 billion years ago). Lyman-alpha blobs are so called because they strongly emit radiation due to the Lyman-alpha emission line of hydrogen gas. Normally, Lyman-alpha emission is in the ultraviolet part of the spectrum, but Lyman-apha blobs are so distant, their light is redshifted to (longer) optical wavelengths. X-ray data (blue) indicates the presence of a supermassive black hole feeding at the center of an active galaxy embedded in the blob. Illustrated close up in the right hand panel, radiation and outflows from the active galaxy are thought to be a source for energizing and heating the blob's hydrogen gas. In fact, Lyman-alpha blobs could represent an early phase in galaxy formation where the heating is so great it begins to limit further rapid growth of active galaxies and their supermassive black holes.

先上APOD大图，2048X1219
http://apod.nasa.gov/apod/image/0907/labs2048_multiCXC.jpg

                               
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今天的成大翻译，北京天文馆的还没翻译呢。
http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/apod.html

Lyman-α雲球
影像提供: NASA / ESA, CXC, JPL-Caltech, STScI, NAOJ, J.E. Geach (Univ. Durham) et al.
示意圖: NASA/CXC/M.Weiss
說明:
左方這張驚人的影像，是Lyman-α雲球，有著延展數十萬光年的巨大氫氣雲，這張分別有地表與太空望遠鏡所拍攝的X射線、光學，以及近紅外波段影像。這個巨型像變形蟲的結構，大概是宇宙 20億年的時候產生，大概已經是120億年前的事情了。Lyman-α雲球名字的緣由是因為在氫氣的Lyman-α譜線有強發射。正常來說，Lyman-α發射譜線為紫外光，但是Lyman-α雲球卻是紅位移到遙遠的可見光波段。同時在X射線(藍色)顯示，雲球有個超大能量的黑洞，餵養著中心的活躍星系。從右方的示意圖中，認為活躍星系的輻射與外流加熱了雲球。事實上，Lyman-α雲球可能代表活躍星系形成的初期，由於強烈的加熱而限制了活躍星系與巨大黑洞的快速成長。

今天的成大翻译实在糟糕，大家可能看得一头雾水，我想需要说明几点。
1、Lyman-α辐射是氢原子的发射谱线，比我们常说的H-α能级高，各谱线对应的电子回到基态。
2、左图是合成的，蓝色光点是钱德拉卫星的成像，其余的是地面望远镜的成像
3、超级黑洞是活跃星系的驱动力，但不能说是饲养着吧。活跃星系和黑洞的成长需要大量的物质，强烈的加热作用使物质离开了核心区，就会抑制黑洞的成长。

漂亮啊

这是今天的图吧，怎么是7.1？

发帖时标题使用了缓存的缘故，没注意。已经改正，谢谢江版提醒。

7# gohomeman1


不客气

好靓吖！！！