NGC 4845: Hubble Space Telescope Sees Large Spiral Galaxy

NGC 4845, otherwise known as LEDA 44392 or UGC 8078, is an 11th magnitude spiral galaxy in the constellation of Virgo. It is 58.8 million light-years away from us. The galaxy was originally discovered by the German-born British astronomer William Herschel in 1786.

According to astronomers, NGC 4845 hosts a supermassive black hole in its center. The presence of a black hole in a distant galaxy like this one can be inferred from its effect on the galaxy’s innermost stars; these stars experience a strong gravitational pull from the black hole and whizz around the galaxy’s center much faster than otherwise.

image_3542e-NGC-4845

From investigating the motion of these central stars, astronomers can estimate the mass of the central black hole – for NGC 4845 this is estimated to be hundreds of thousands times heavier than the Sun. This same technique was also used to discover the supermassive black hole at the center of our own Milky Way Galaxy – Sagittarius A* – which hits some 4 million solar masses.

In 2013 European astronomers were observing another galaxy when they noticed an energetic flare from the NGC 4845’s core. The flare came from the supermassive black hole tearing up and feeding off an object of 14 – 30 Jupiter masses. A brown dwarf or a so-called super-Jupiter exoplanet simply strayed too close and was devoured by the hungry black hole.

“The observation was completely unexpected, from a galaxy that has been quiet for at least 20-30 years,” the astronomers said.

This image includes optical and infrared observations from Hubble’s Wide Field Planetary Camera 2 (WFPC2).

 

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