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At first glance, there’s nothing remarkable about the galaxy NGC 1600. It’s a little bit bigger than our home galaxy, the Milky Way, but it looks plain and uninspiring. It’s an elliptical galaxy, which means it looks a bit like a glowing, fuzzy rugby ball.
When astronomers peered deep into the heart of NGC 1600, though, they found something that is remarkable: one of the biggest black holes yet seen. It’s about 4,000 times the mass of the black hole at the center of the Milky Way.
The astronomers studied the galaxy with several telescopes on the ground, including one at McDonald Observatory, as well as with Hubble Space Telescope. In particular, they measured the motions of stars near the galaxy’s heart. How fast the stars move reveals the mass of the object they’re orbiting — in this case, a supermassive black hole.
The astronomers say the black hole may have grown so large by merging with the black holes in several smaller galaxies. That process also cleared out most of the stars in the center of NGC 1600. Without stars to feed on, the black hole is dark and quiet.
NGC 1600 is about 200 million light-years away, in the constellation Eridanus, the river, which meanders across the southern sky tonight. Not long after night falls, the galaxy stands above Rigel, the brightest star of the adjoining constellation Orion. It’s so faint, though, that you need a telescope to see it.
We’ll have more about black holes tomorrow.
Script by Damond Benningfield