3色合成的M51
Object name: M51, Messier 51, Whirlpool Galaxy, NGC 5194Object type: Galaxy pair
Distance: 37 million light-years or 11 Mpc
Constellation: Canes Venatici
Magnitude: 8.4
M51,其名字来源于第51个编进梅西耶天体编目里的天体，并被认为是最典型的螺旋星系，距离地球30000000光年，其也是夜晚星空中最亮的一个星系。这是一张M51的复合图象，众所周知他是旋涡星系，通过几个NASA的沿轨道航行的空间天文台这种引人注目的方式展现出他的高贵。来自NASA的钱得拉X射线天文台的X射线的数据显示出黑洞和中子星这个双星系统的起源要点。钱德拉同样也能探测出弥散在空间里的从双星间渗透出的热气。光学波段的数据来自哈勃空间望远镜（绿色的）红外射线来自斯必泽空间望远镜（红色）两个在旋臂里加亮的长道是由带有尘埃的气体和恒星组成。这张M51通过GALEX望远镜显示出热，年轻的恒星制造出很多紫外辐射能（蓝色）
在教科书上M51的旋涡结构被认为是经历了和银河系邻近的NGC5195撞击的结果，看上去他在上面，一些模拟结果表明M51形成旋涡形状部分原因是在500000000年前当MGC5195经过M51主要的圆盘时所导致的。这样的重力拖拽之战也许也是触发M51中恒星形成水平高低的原因。相伴的星系拉力会通过压缩气体来促使额外恒星的形成，跳跃式的启动过程靠恒星的形成。
M51, whose name comes from being the 51st entry in Charles Messier's catalog, is considered to be one of the classic examples of a spiral galaxy. At a distance of about 30 million light years from Earth, it is also one of the brightest spirals in the night sky. A composite image of M51, also known as the Whirlpool Galaxy, shows the majesty of its structure in a dramatic new way through several of NASA's orbiting observatories. X-ray data from NASA's Chandra X-ray Observatory reveals point-like sources (purple) that are black holes and neutron stars in binary star systems. Chandra also detects a diffuse glow of hot gas that permeates the space between the stars. Optical data from the Hubble Space Telescope (green) and infrared emission from the Spitzer Space Telescope (red) both highlight long lanes in the spiral arms that consist of stars and gas laced with dust. A view of M51 with the GALEX telescope shows hot, young stars that produce lots of ultraviolet energy (blue).
The textbook spiral structure is thought be the result of an interaction M51 is experiencing with its close galactic neighbor, NGC 5195, which is seen just above. Some simulations suggest M51's sharp spiral shape was partially caused when NGC 5195 passed through its main disk about 500 million years ago. This gravitational tug of war may also have triggered an increased level of star formation in M51. The companion galaxy's pull would be inducing extra starbirth by compressing gas, jump-starting the process by which stars form.
仍然原创翻译+星系数据说明
URL：http://gallery.spitzer.caltech.e ... mage_name=sig07-024
大图
http://ipac.jpl.nasa.gov/media_images/sig07-024.jpg
[ 本帖最后由 江涛 于 2008-2-16 23:10 编辑 ] 漂亮！::070821_09.jpg:: 不管先后，还是支持江兄的翻译.
[ 本帖最后由 寻找拉玛 于 2008-2-17 00:30 编辑 ] 不好意思，如果是这样，那就关闭把
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