Galaxy NGC 4889 Contains a Giant Black Hole
Posted on February 20, 2016
The NASA/ESA Hubble Space Telescope shared this new image of the elliptical galaxy NGC 4889. A gigantic black hole lurks at the center of this galaxy although it cannot be seen in the image.Astronomers estimate that the supermassive black hole in NGC 4889 has a mass twenty-one billion times that of the Sun. It also has an event horizon with a diameter of about 130 billion kilometers (80 billion miles). By comparison the black hole at the center of the Milky Way has a mass about four million times that of the Sun and a diameter of about 93 million miles. The diameter of our galaxy's black hole was downsized in a study last year.
Astronomers say NGC 4889's black hole is currently in a dormant phase. It is resting after many years of consuming stars and dust clouds. Astronomers cannot directly observe a black hole but its mass can be indirectly determined. Astronomers used instruments on the Keck II Observatory and Gemini North Telescope to measure the velocity of the stars moving around NGC 4889's center. These velocities were then used to measure the mass of the supermassive black hole.
You can view a hi-res version of the above image here on the Hubble website. Here is a video that zooms into the galaxy NGC 4889: