2025年2月26日
Einstein Ring Surrounds Nearby Galaxy Center
Image Credit & Copyright: ESA, NASA, Euclid Consortium; Processing: J.-C. Cuillandre, G. Anselmi, T. Li
Explanation: Do you see the ring? If you look very closely at the center of the featured galaxy NGC 6505, a ring becomes evident. It is the gravity of NGC 6505, the nearby (z = 0.042) elliptical galaxy that you can easily see, that is magnifying and distorting the image of a distant galaxy into a complete circle. To create a complete Einstein ring there must be perfect alignment of the nearby galaxy’s center and part of the background galaxy. Analysis of this ring and the multiple images of the background galaxy help to determine the mass and fraction of dark matter in NGC 6505’s center, as well as uncover previously unseen details in the distorted galaxy. The featured image was captured by ESA‘s Earth-orbiting Euclid telescope in 2023 and released earlier this month.
Tomorrow’s picture: open space
邻近星系核心周围的爱因斯坦环
影像提供与版权: ESA, NASA, Euclid Consortium; 影像处理: J.-C. Cuillandre, G. Anselmi, T. Li
说明: 见到环状结构了吗？如果仔细检视这幅以星系NGC 6505为主题的影像，在其核心附近可找到一个清晰可辨的光环。这个环绕邻近椭圆星系 NGC 6505（红移z=0.042）核心的光环，其成因是此星系的重力场放大并扭曲了遥远星系的身影，把它拉扯成完整的环。要产生这个完整的爱因斯坦环，远近二个星系的对齐要极为精确，亦即近处星系的中心与背景星系部分区域要恰好位于同一直线上。分析这个爱因斯坦环及背景星系的多重影像，不仅可以帮助科学家测定星系NGC 6505核心的暗物质之质量及其比例，同时还能借以找出这个身形扭曲的背景星系先前未见的细微结构。这幅本月初刚发布的主题影像，是由欧洲航天局的欧几里得太空望远镜摄于于2023年。
明日的图片: open space
