NGC 4753扭曲的星系盘

NGC 4753扭曲的星系盘

The Twisted Disk of NGC 4753
Image Credit: NASA, ESA, Hubble; Processing: Alexander Reinartz

Explanation: What do you think this is? Here’s a clue: it’s bigger than a bread box. Much bigger. The answer is that pictured NGC 4753 is a twisted disk galaxy, where unusual dark dust filaments provide clues about its history. No one is sure what happened, but a leading model holds that a relatively normal disk galaxy gravitationally ripped apart a dusty satellite galaxy while its precession distorted the plane of the accreted debris as it rotated. The cosmic collision is hypothesized to have started about a billion years ago. NGC 4753 is seen from the side, and possibly would look like a normal spiral galaxy from the top. The bright orange halo is composed of many older stars that might trace dark matter. The featured Hubble image was recently reprocessed to highlight ultraviolet and red-light emissions.

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NGC 4753扭曲的星系盘
影像提供: NASA, ESA, Hubble; Processing: Alexander Reinartz

说明: 你觉得这是什么？提示：它比面包盒大，大非常非常多。影像中的NGC 4753是个扭曲的盘状星系，其不寻常的黝黑丝状尘埃为它的历史提供了线索。虽然没有人能确定发生了什么，但有主流模型认为，它原先算是正常的盘状星系，后来用重力撕碎了一个满是尘埃的伴星系，在此同时，大星系本身的进动扭曲了残骸的吸积面，而自转则更进一步形成这种独特的形状。这场宇宙级碰撞，臆测大约始于10亿年前。不过，侧向的NGC 4753如果从盘面上方俯视，看起来或许会像是普通的螺旋星系。此星系明亮橙色星系晕来自其内的大量年老恒星，而这些恒星或许勾勒出暗物质的分布。这幅由哈勃望远镜拍摄的主题影像，最近经过重新处理，以突显其内的紫外光和红光辐射。

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