Astronomy Picture of the Day

Explanation: This dramatic image of an interacting pair of galaxies was made using the 1.5 meter telescope at the Cerro Tololo Inter-American Observatory near La Serena, Chile. NGC 1531 is the background galaxy with a bright core just above center and NGC 1532 is the foreground spiral galaxy laced with dust lanes. The pair is about 70 million light-years away in the southern constellation Eridanus. These galaxies lie close enough together so that each feels the influence of the other's gravity. The gravitational tug-of-war has triggered star formation in the foreground spiral as evidenced by the young, bright blue star clusters along the edge of the front spiral arm. Though the spiral galaxy in this pair is viewed nearly edge-on, astronomers believe the system is similar to the face-on spiral and companion known as M51, the Whirlpool Galaxy.

這張戲劇性的星系互擾影像，是由智利．拉塞雷納附近的托洛洛山美洲天文台之1.5米口徑望遠鏡所拍攝的。 位於影像中上方的NGC 1531，是個有明亮核心的背景星系，而NGC 1532則是一個鑲著塵埃帶的前景螺旋星系。 這對星系位於南天波江座方向，距離地球約7000萬光年遠之處。 這些星系彼此夠鄰近，因此會受到彼此的重力之影響。 在前景螺旋星系的前螺旋臂邊緣上，眾多的明亮藍色星團，即可見證星系交互作用會引發恆星形成活動。 儘管這對星系中的螺旋星系近乎側向，但天文學家認為這對星系，酷似正向螺旋星系M51（渦狀星系）和它的伴星系。