Astronomy Picture of the Day——NGC 4676：双鼠星系
NGC 4676: The Mighty Mice
Image Credit & Copyright: BruceWaddington
Explanation: These two mighty galaxies arepulling each other apart. Known as The Mice because they have such long tails,each large spiral galaxy has actually passed through the other. Their longtails are drawn out by strong gravitational tides rather than collisions oftheir individual stars. Because the distances are so large, the cosmicinteraction takes place in slow motion -- over hundreds of millions of years.They will probably collide again and again over the next billion years untilthey coalesce to form a single galaxy. NGC 4676 lies about 300 millionlight-years away toward the constellation of Bernice's Hair (Coma Berenices)and are likely members of the Coma Cluster of Galaxies. Not often imaged insmall telescopes, this field of view catches the faint tidal tails severalhundred thousand light-years long.
NGC 4676：双鼠星系
这两个庞大的星系正在拉开彼此。它们之所以被称为双鼠星系是因为它们具有长长的尾巴，实际上这两个大型漩涡星系每一个都穿过了另外一个。它们的长尾巴是被强烈的引力潮牵引出来，而不是星系中单个恒星的碰撞产生的。因为它们距离地球如此之远，所以宇宙间的相互作用是以慢动作的方式发生，通常要经历数亿年。而在接下来的十亿年里，它们可能会发生一次又一次地碰撞，直至合并成一个星系为止。NGC 4676位于后发座方向、距离地球大约3亿光年，很可能也是后发星系团的成员。图像中宽阔的视野使用小型望远镜基本看不到，但这里它捕捉到了数十万光年长的黯淡潮汐尾。
参考文献：
https://apod.nasa.gov/apod/image/1906/Mice_LRGB_web.jpg
近期文章：
Astronomy Picture of the Day——哈勃拍摄的M96