Merging Galaxies Illuminate The Cosmic Food Chain
Scientists studying a ‘twin’ of the Milky Way have used the W. M. Keck Observatory and Subaru Observatory to accurately model how it is swallowing another, smaller galaxy. Their findings have opened the way to a better understanding of how structure forms in the universe and are being published in the Monthly Notices of the Royal Astronomical Society this week.
The work, led by Caroline Foster of the Australian Astronomical Observatory, has used the Umbrella (NGC 4651) galaxy to reveal insights in galactic behavior.
The Umbrella lies 62 million light-years away, in the northern constellation of Coma Berenices. Its faint parasol is composed of a stellar stream, thought to be the remnants of a smaller galaxy being pulled apart by the large galaxy’s intense gravitational field. The Umbrella will eventually absorb this small galaxy completely.
The merging of small galaxies into larger ones is common throughout the universe, but because the shredded galaxies are so faint it has been hard to extract details in three-dimensions about how such mergers proceed.