Arp 273的特殊星系

Arp 273的特殊星系

Peculiar Galaxies of Arp 273
Image Credit & Copyright: Dave Doctor

Explanation: The colorful, spiky stars are in the foreground of this image taken with a small telescope on planet Earth. They lie well within our own Milky Way Galaxy. But the two eye-catching galaxies in the frame lie far beyond the Milky Way, at a distance of over 300 million light-years. The galaxies’ twisted and distorted appearance is due to mutual gravitational tides as the pair engage in close encounters. Cataloged as Arp 273 (also as UGC 1810), these galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. Closer to home, the large spiral Andromeda Galaxy is known to be some 2 million light-years away and inexorably approaching the Milky Way. In fact the far away peculiar galaxies of Arp 273 may offer an analog of the far future encounter of Andromeda and Milky Way. Repeated galaxy encounters on a cosmic timescale ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years.

Tomorrow’s picture: pixels in space

Arp 273的特殊星系
影像提供与版权: Dave Doctor

说明: 在这幅用地面小望远镜拍摄的影像里，带芒色彩缤纷的前景恒星近在银河系之内。而这两个很吸睛的星系，则位于银河系后方3亿多光年远处。它们扭曲的外观，源自这对星系彼此接近时的重力潮汐效应。编录号为Arp 273（亦称UGC 1810）的这对星系，外观诚然很特殊，但这种互扰星系，在目前的宇宙其实很常见。例如：离我们约2百万光年远的仙女座大星系，就不停地往银河系靠，因此，Arp 273可能是仙女座星系与银河系遥远未来近距离互扰的预告。在长长的宇宙时间尺度期间，如果星系重覆接近，它们最后会合拼成单一星系。从地球看出去，星系对Arp 273的明亮星系核相隔约100,000光年。

明日的图片: pixels in space