2022年7月5日

这张特色图片显示了一个遥远的星系被引力透镜扭曲成围绕星系团中心的巨大弧线。请参阅说明以获取更多详细信息。

A Molten Galaxy Einstein Ring
Image Credit:
ESA/Hubble & NASA, S. Jha; Processing: Jonathan Lodge

Explanation: It is difficult to hide a galaxy behind a cluster of galaxies. The closer cluster’s gravity will act like a huge lens, pulling images of the distant galaxy around the sides and greatly distorting them. This is just the case observed in the featured image recently re-processed image from the Hubble Space Telescope. The cluster GAL-CLUS-022058c is composed of many galaxies and is lensing the image of a yellow-red background galaxy into arcs seen around the image center. Dubbed a molten Einstein ring for its unusual shape, four images of the same background galaxy have been identified. Typically, a foreground galaxy cluster can only create such smooth arcs if most of its mass is smoothly distributed — and therefore not concentrated in the cluster galaxies visible. Analyzing the positions of these gravitational arcs gives astronomers a method to estimate the dark matter distribution in galaxy clusters, as well as infer when the stars in these early galaxies began to form.

New APOD Social Mirrors in Arabic: On Facebook, Instagram, and Twitter

Tomorrow’s picture: star streamers


熔融星系的爱因斯坦环
影像提供:
ESA/Hubble & NASA, S. Jha; 影像处理: Jonathan Lodge

说明: 要把星系藏在另一个星系团的后方,是有点难度的工作。因为较邻近的星系团之重力,行为像庞大的透镜,会弯曲遥远星系的影子,让它折绕过星系团边缘并发生显著的扭曲。这幅最近重新处理哈勃太空望远镜数据所得的主题影像,即可为佐证。影像中由许多星系聚成的星系团GAL-CLUS-022058c,把黄红色背景星系的身影会聚成环拱在中心周围的数片光弧。而从这组形状独特而有熔融爱因斯坦环昵称的透镜弧,至少可辨识出隶属于同一个背景星系的4重影子。前景星系团要产生这么平滑的光弧,通常其质量要大致均匀分布,而且不仅限于星系团的可见区域之内。分析这些引力透镜弧所在的位置,让天文学家得以粗估星系团内的暗物质如何分布,也可据以推断这些早期星系内的恒星何时开始形成。

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明日的图片: star streamers

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