这是最新公布的M31的红外图，估计几天后APOD会发的，我就先贴在这里，APOD发的时候再注解一下吧，今天的CCTV1中已经提到了。
http://www.nasa.gov/mission_pages/WISE/multimedia/pia12832-c.html
02.17.10
Our Neighbor Andromeda
2010.2.17：我们的近邻——仙女座大星系的红外光图像
The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this new image from NASA's Wide-field Infrared Survey Explorer, or WISE. The mosaic covers an area equivalent to more than 100 full moons, or five degrees across the sky. WISE used all four of its infrared detectors to capture this picture (3.4- and 4.6-micron light is colored blue; 12-micron light is green; and 22-micron light is red). Blue highlights mature stars, while yellow and red show dust heated by newborn, massive stars.
NASA的广域红外巡天探测器（WISE）拍摄了庞大的仙女座大星系（又称梅西耶31#天体，缩写M31）的最新红外光全图。这张拼接图像的视场面积超过100个满月，相当于5平方度的天区。WISE使用了它全部4个红外通道以获取此图像，它们的配色如下：3.4、4.6微米，蓝；12微米，绿；22微米，红。蓝色突出显示成熟的老年恒星，而红色、黄色则表示被新形成的大质量恒星加热的尘埃辐射。
Andromeda is the closest large galaxy to our Milky Way galaxy, and is located 2.5 million light-years from our sun. It is close enough for telescopes to spy the details of its ringed arms of new stars and hazy blue backbone of older stars. Also seen in the mosaic are two satellite galaxies, known as M32, located just a bit above Andromeda to the left of center, and the fuzzy blue M110, located below the center of the great spiral arms. These satellites are the largest of several that are gravitationally bound to Andromeda.
M31离太阳约250万光年，是离银河系最近的巨型星系。它离我们如此之近，足够望远镜解析出年轻恒星组成的环状旋臂和老年恒星组成的朦胧蓝色背景晕的细节。图中还能看到M31的两个伴星系，其中M32是位于M31中心左上的蓝色小斑点，而M110是位于下方的蓝色模糊团块。它们是被M31引力束缚的矮星系中最大的2个。
The Andromeda galaxy is larger than our Milky Way and contains more stars, but the Milky Way is thought to perhaps have more mass due to its larger proportion of a mysterious substance called dark matter. Both galaxies belong to our so-called Local Group, a collection of more than 50 galaxies, most of which are tiny dwarf systems. In its quest to map the whole sky, WISE will capture the entire Local Group.
M31比银河系大，也包含更多的恒星。不过，现在也有认为银河系更重的，原因是它含有巨量的神秘物质——暗物质。银河系和仙女座大星系主宰了本星系群，它是一个含有50个以上星系的集群，当然大部分是微型矮星系。在WISE的全天空巡天历程中，它将拍摄整个本星系群的图像。
Image credit: NASA/JPL-Caltech/UCLA
图像版权：美国宇航局（NASA），加州理工学院，喷气推进实验室（JPL），加州大学洛杉矶分校（UCLA） |
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