Another possible explanation is that the bubble was created by radiation from the quasar before it faded. In this scenario, the energy produced by the supermassive black hole has changed from that of a quasar, when energy is radiated in a broad beam, to more concentrated output in the form of collimated jets of particles and consistent with the observed radio emission in this source. The center of the X-ray emission shows cooler gas, which astronomers interpret as a large bubble in the gas.Īstronomers suspect this bubble may have been created when a pair of jets from the black hole blew away the hot gas. The evidence for this change in the black hole’s activity comes from hot gas in the center of IC 2497 detected in a long exposure by Chandra.

New observations with Chandra show that the black hole is still producing large amounts of energy even though it is no longer generating intense radiation as a quasar. In this new composite image of IC 2497 (top object) and the Green Blob (bottom), X-rays from Chandra are purple and optical data from the Hubble Space Telescope are red, green, and blue. In this scenario, the blob would become much dimmer in the distant future, as reduced ultraviolet and X-radiation levels from the faded quasar finally reach the cloud. If the black hole was growing at a much higher rate in the past and then slowed down dramatically in the past 200,000 years, the glow of the Green Blob could be consistent with the present low activity of the black hole. Such a black hole would produce copious amounts of radiation from infalling material, categorizing it as a “quasar.” However, the distance of the Green Blob from IC 2497 is large enough that we may be observing a delayed response, or an echo of past activity, from a rapidly growing black hole. At present the black hole is growing slowly and not producing nearly enough radiation to cause such a glow. This object was discovered in 2007 by Hanny van Arkel, at the time a school teacher, as part of the citizen science project called Galaxy Zoo.Īstronomers think that a blast of ultraviolet and X-radiation produced by a supermassive black hole at the center of the galaxy IC 2497 (only 200,000 light years away) excited the oxygen atoms in a gas cloud, giving the Green Blob its emerald glow. The Green Blob, a renowned cosmic structure also called “Hanny’s Voorwerp” (which means “Hanny’s object” in Dutch), is located about 680 million light years from Earth. Using data from NASA’s Chandra X-ray Observatory and other telescopes, astronomers are piecing together clues from a cosmic “blob” and a gas bubble that could be a new way to probe the past activity of a giant black hole and its effect on its host galaxy. Two cosmic structures show evidence for a remarkable change in behavior of a supermassive black hole in a distant galaxy.

Mass effect black blob