The Hubble Space Telescope has photographed the eerie, green-glowing gas highlighted by a recently deceased quasar.
The Milky-Way-sized object, located about 730 million light-years away, surrounds a supermassive black hole that was once the heart of a galaxy.
The black hole gobbled up its last available meal of gas and dust as a quasar between 45,000 and 70,000 years ago, ionizing oxygen in distant gas clouds into a bright green glow before fading back into darkness. The glowing gas cloud, known as Hanny’s Voorwerp, is now 100 to 10,000 times dimmer than the quasar was when it was still devouring matter.
The green object is named after Hanny van Arkel, the Dutch schoolteacher who discovered it in 2007 while helping classify more than 60 million galaxies for the Galaxy Zoo project.
In the new Hubble image (above) of Hanny’s Voorwerp, taken with Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys, the nearby spiral galaxy IC 2497 is helping to spark star formation in the yellow-orange fringes of the Voorwerp. The new stars are a few million years old.
Original Article: http://www.wired.com/wiredscience/2011/01/hannys-voorwerp-quasar-hubble/