江涛
发表于 2008-7-23 15:58
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来自： 中国–江苏–常州 电信/网宿科技股份有限公司电信CDN节点
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The Pinwheel galaxy, otherwise known as Messier 101, sports bright reddish edges in this new infrared image from NASA's Spitzer Space Telescope. Research from Spitzer has revealed that this outer red zone lacks organic molecules present in the rest of the galaxy. The red and blue spots outside of the spiral galaxy are either foreground stars or more distant galaxies.
The organics, called polycyclic aromatic hydrocarbons, are dusty, carbon-containing molecules that help in the formation of stars. On Earth, they are found anywhere combustion reactions take place, such as barbeque pits and exhaust pipes. Scientists also believe this space dust has the potential to be converted into the stuff of life.
Spitzer found that the polycyclic aromatic hydrocarbons decrease in concentration toward the outer portion of the Pinwheel galaxy, then quickly drop off and are no longer detected at its very outer rim. According to astronomers, there's a threshold at the rim where the organic material is being destroyed by harsh radiation from stars. Radiation is more damaging at the far reaches of a galaxy because the stars there have less heavy metals, and metals dampen the radiation.
The findings help researchers understand how stars can form in these harsh environments, where polycyclic aromatic hydrocarbons are lacking. Under normal circumstances, the polycyclic aromatic hydrocarbons help cool down star-forming clouds, allowing them to collapse into stars. In regions like the rim of the Pinwheel -- as well as the very early universe -- stars form without the organic dust. Astronomers don't know precisely how this works, so the rim of the Pinwheel provides them with a laboratory for examining the process relatively close up.
In this image, infrared light with a wavelength of 3.6 microns is colored blue; 8-micron light is green; and 24-micron light is red. All three of Spitzer's instruments were used in the study: the infrared array camera, the multiband imaging photometer and the infrared spectrograph.
补上翻译（自翻）
轮转烟火星系，或者也被叫做M101，在来自NASA斯必泽空间望远镜拍摄的新的红外照片中展现出了其边缘炫耀明亮的红色条带。来自斯必泽的研究指出在星系的其余外层红色区域都缺乏有机分子。漩涡星系外周的红色和蓝色点都是前景星或者距离星系很远。
有机物，被叫做多环的芳烃，是一些尘埃，含碳分子帮助恒星的形成。在地球上，他们能被任何发生燃烧反应的地方，例如烤肉坑和排气管中。科学家坚信这些太空尘埃有被转换成生命原料的潜力。
斯必泽发现多环芳烃集中在轮转烟火星系外部减少，并且很快下降，在最外缘处不再能被探测到。通过天文学家分析，在有机物质被来自恒星的剧烈辐射破坏的地方存在一个门限。辐射在远离星系的地方更具破坏性，因为在那个区域仅含很少量的金属——金属能减少辐射。
这个发现帮助研究人员理解恒星是如何在此种苛刻环境下（缺乏多环芳烃）诞生的。在正常情况下，多欢芳烃帮助冷却下来的恒星形成星云，并让他们再恒星内部崩解。就好比轮转烟火星系的外部区域——和早期宇宙极其相似——恒星诞生不靠有机尘埃。天文学家不知道这是如何精确运行的，因此轮转火焰星系外缘提供他们一个类似实验室相对仔细的检查过程。
这张图片中，红外光是3.6微米波段的，以蓝色标记，8微米的光以绿色标记，24微米的光以红色标记。斯必泽上所有用于研究的仪器一共有3样：红外列阵照相机、多频段图片光度计和红外频谱图仪。
URL:http://gallery.spitzer.caltech.e ... ge_name=ssc2008-14a
由于信息是拉玛提供，为了时效性，所以就先放图，翻译等下送出。。。。。
[ 本帖最后由 江涛 于 2008-7-23 21:23 编辑 ] |
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