The Local Group is the gravitationally bound group of galaxies dominated by the Milky Way and Andromeda, each with its satellite galaxies. A galaxy cluster is one of the largest gravitationally bound systems: many galaxies held, with a hot gas that radiates X-rays, in a common well of mostly dark matter.
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Earth and Space Sciences · 术语表
什么是 Local Group; galaxy cluster?
又称: Local Group · galaxy cluster