不规则星系NGC 55

2019 July 12

Magellanic Galaxy NGC 55
Image Credit & Copyright: Acquisition – Eric Benson, Processing – Dietmar Hager

Explanation: Irregular galaxy NGC 55 is thought to be similar to the Large Magellanic Cloud (LMC). But while the LMC is about 180,000 light-years away and a well-known satellite of our own Milky Way Galaxy, NGC 55 is more like 6 million light-years distant, a member of the Sculptor Galaxy Group. Classified as an irregular galaxy, in deep exposures the LMC itself resembles a barred disk galaxy. Spanning about 50,000 light-years, NGC 55 is seen nearly edge-on though, presenting a flattened, narrow profile in contrast with our face-on view of the LMC. Just as large star forming regions create emission nebulae in the LMC, NGC 55 is also seen to be producing new stars. This highly detailed galaxy portrait highlights a bright core crossed with dust clouds, telltale pinkish star forming regions, and young blue star clusters in NGC 55.

不规则星系NGC 55
影像来源与版权: Acquisition – Eric Benson, 影像处理 – Dietmar Hager

说明：不规则星系NGC 55被认为与大麦哲伦星系（LMC）相似。然而，大麦哲伦星系距离我们约18万光年，是我们银河系的著名卫星星系，而NGC 55距离我们约6百万光年，是玉夫座星系群的成员。在深空曝光影像中，归类为不规则星系的大麦哲伦星系形似一个有棒的盘状星系。NGC 55的大小约5万光年，看起来几乎是侧向的，它呈现出一个扁平、狭窄的外形，与大麦哲伦星系的正面影像形成了鲜明对比。正如大麦哲伦星系中的大型恒星形成区所形成的发射星云一样，NGC 55也被认为正在孕育新的恒星。这幅极为精细的星系影像呈现了NGC 55内部交织着尘埃云的明亮星系核，以及粉色的恒星形成区和年轻的蓝色星团。