APOD 070411：NGC 4258（M106）的旋臂

不知道该发在这里还是在咖啡屋中，虽然这个是很早的（2007.4.11），我搜索了一下，应该没发过。
原文是http://apod.nasa.gov/apod/ap070411.html

Better known as M106, brightspiral galaxyNGC 4258 is about 30 thousand light years across and21 million light years awaytoward the northern constellationCanes Venatici.The yellow and red hues inthis compositeimage show thegalaxy's sweepingspiral armsas seen in visible andinfrared light.But x-rayand radio data(blue and purple) reveal two extraspiral arms -- arms that don't align with the more familiar tracersof stars, gas, and dust.In fact,an analysis ofthe x-rayand radio data suggeststhat the anamolous arms are composed of materialheated by shock waves.Detected at radio wavelengths,powerful jets originating in thegalaxy's core likely drive the shocks into the diskof NGC 4258.

                               
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大意是NGC 4258又名M106，位于猎犬座北部，离我们2100万光年，本身大小3万光年。从可见光、红外（红、黄两色）复合图像看，是一个正常的涡旋星系，但X射线和射电波（蓝色、紫色）却揭示了这个星系的另外2个扩展旋臂——不是由恒星、尘埃、发光气体显示的。 事实上，有证据表明这扩展臂是热致冲击波。根据无线电波长，是星系核心的强大喷射流在驱动星云盘物质（形成了看不见的旋臂）。
英文比较差，不过我想大概意思没错吧，就像M82那样.

这是一个图片下载链接，http://chandra.harvard.edu/photo/printgallery/2007/#

好像是要从这个下载页面再手动选择下载大小的

我查了一下，2000.2.15也有一个相关帖子
http://apod.nasa.gov/apod/ap000215.html

M106: A Spiral Galaxy with a Strange Core
Credit: Ron & Beth Sharer, Steven White,AOP, KPNO, NOAO, NSF

What's happening at the center of spiral galaxy M106?A swirling disk of stars and gas, M106's appearance is dominated by two bright spiral arms and dark dust lanes near the nucleus.  Bright newly formed stars near their outer tips distinguish the spiral arms in the above photograph.The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy.  An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole.  M106, also designated NGC 4258, is a relatively close 25 million light years away, spans 30 thousand light years across, and can be seen with a small telescope towards the constellation of Canes Venatici.

                               
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意思比较简单，就不翻译了（太迟了想睡觉了）。

这张更小，估计是地面望远镜拍摄的

                               
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拍摄的挺壮观的~顶一个~楼主辛苦了！！

非常漂亮.顶一个