Astronomy Picture of the Day——宇宙碰撞造就的星系环
Cosmic Collision Forges Galactic Ring
Image Credit: X-ray: Chandra (NASA); Optical: Hubble (NASA)
Explanation: How could a galaxy becomeshaped like a ring? The rim of the blue galaxy pictured on the right is animmense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741, is known as a ring galaxy and was caused by an immense galaxy collision. When galaxies collide, they pass through each other -- their individual stars rarely comeinto contact. The ring-like shape is the result of the gravitational disruptioncaused by an entire small intruder galaxy passing through a large one. Whenthis happens, interstellar gas and dust become condensed, causing a wave ofstar formation to move out from the impact point like a ripple across thesurface of a pond. The likely intruder galaxy is on the left of this combined image from Hubble (visible) and Chandra (X-ray) space telescopes. X-ray lightis shown in pink and depicts places where energetic black holes or neutronstars, likely formed shortly after the galaxy collision, reside.
宇宙碰撞造就的星系环
一个星系怎么才能变成环形的结构？这幅图像右侧蓝色星系的边缘是由极其明亮且数量众多的新生大质量恒星所构成的巨大环状结构，其直径达15万光年。这个以环状星系闻名的星系编号为AM 0644-741，它是由一次巨大的星系碰撞产生的。当星系发生碰撞时，它们贯穿彼此，但它们各自内部的恒星却很少发生接触。环状结构是由于小星系贯穿大星系时引起的引力瓦解所导致的。星际云气和尘埃发生凝结，导致一片恒星形成区从撞击点移出，如同穿过池塘表面的一道涟漪。位于图像左侧的可能就是入侵星系，它由哈勃太空望远镜（可见光）和钱拉德太空望远镜（X射线）拍摄的影像所合成的。另外，X射线下所呈现的粉红色描绘了在星系碰撞不久之后可能形成的高能黑洞或中子星驻留的位置。
参考文献：
https://apod.nasa.gov/apod/image/1809/Ring0644_HubbleChandra_3348.jpg
近期文章：
Astronomy Picture of the Day——船底座大星云