NGC 147与NGC 185



NGC 147 and NGC 185
Image Credit & Copyright:
Dan Bartlett

Explanation: Dwarf galaxies NGC 147 (left) and NGC 185 stand side by side in this sharp telescopic portrait. The two are not-often-imaged satellites of M31, the great spiral Andromeda Galaxy, some 2.5 million light-years away. Their separation on the sky, less than one degree across a pretty field of view, translates to only about 35 thousand light-years at Andromeda’s distance, but Andromeda itself is found well outside this frame. Brighter and more famous satellite galaxies of Andromeda, M32 and M110, are seen closer to the great spiral. NGC 147 and NGC 185 have been identified as binary galaxies, forming a gravitationally stable binary system. But recently discovered faint dwarf galaxy Cassiopeia II also seems to be part of their system, forming a gravitationally bound group within Andromeda’s intriguing population of small satellite galaxies.

Tomorrow’s picture: pixels in space

NGC 147与NGC 185
Dan Bartlett

说明: 在这幅清晰的望远镜影像里,矮星系NGC 147(左)和NGC 185并排而立。它们是螺旋仙女大星系(M31)少为人们拍摄的伴星系。在这片美丽星场,这二个在天空相距不到1度的天体,以位在这片视野之外的仙女大星系之距离来换算,相隔大约只有3万5千光年。仙女大星系较明亮的伴星系M32和M110,则靠这个宏伟的螺旋仙女大星系更近。NGC 147与NGC 185经证实,在重力结构上是个稳定的双星系系统。不久前才发现的昏暗矮星系仙女 II(Cassiopeia II),看似也为这个系统的一部分,在仙女大星系为数众多的小伴星系里,形成以重力聚集的小伴星系群。

明日的图片: pixels in space