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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環(huán) 一個星系怎么才能變成環(huán)形的結構？這幅圖像右側藍色星系的邊緣是由極其明亮且數(shù)量眾多的新生大質量恒星所構成的巨大環(huán)狀結構，其直徑達15萬光年。這個以環(huán)狀星系聞名的星系編號為AM 0644-741，它是由一次巨大的星系碰撞產(chǎn)生的。當星系發(fā)生碰撞時，它們貫穿彼此，但它們各自內部的恒星卻很少發(fā)生接觸。環(huán)狀結構是由于小星系貫穿大星系時引起的引力瓦解所導致的。星際云氣和塵埃發(fā)生凝結，導致一片恒星形成區(qū)從撞擊點移出，如同穿過池塘表面的一道漣漪。位于圖像左側的可能就是入侵星系，它由哈勃太空望遠鏡（可見光）和錢拉德太空望遠鏡（X射線）拍攝的影像所合成的。另外，X射線下所呈現(xiàn)的粉紅色描繪了在星系碰撞不久之后可能形成的高能黑洞或中子星駐留的位置。 參考文獻： https://apod./apod/image/1809/Ring0644_HubbleChandra_3348.jpg 近期文章： Astronomy Picture of the Day——船底座大星云 |
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