Latest Active galactic nucleus Stories
GREENBELT, Md., Jan. 6 /PRNewswire-USNewswire/ -- An ongoing X-ray survey undertaken by NASA's Swift spacecraft is revealing differences between nearby active galaxies and those located about halfway across the universe. Understanding these differences will help clarify the relationship between a galaxy and its central black hole. (Logo: http://www.newscom.com/cgi-bin/prnh/20081007/38461LOGO) "There's a lot we don't know about the workings of supermassive black holes," says Richard...
Seeing the shape of material around black holes for first timeBlack holes can now be thought of as donut holes. The shape of material around black holes has been seen for the first time: an analysis of over 200 active galactic nuclei"”cores of galaxies powered by disks of hot material feeding a super-massive black hole"”shows that all have a consistent, ordered physical structure that seems to be independent of the black hole's size."This should be a very messy and complicated...
XMM-Newton has uncovered a well-tuned periodic signal from a super-massive black hole lodged at the centre of a galaxy, ending a long quest for such an object. The discovery provides scientists with a clearer picture on black hole accretion processes and an excellent tool to study active galactic nuclei (AGNs).These periodic signals originating from the black hole are emitted in X-rays, which are blocked out by the Earth's atmosphere. So the team used data from ESA's orbiting X-ray...
For the first time, a team of international researchers has found a way to view the accretion disks surrounding black holes and verify that their true electromagnetic spectra match what astronomers have long predicted they would be. Their work will be published in the July 24 issue of the science journal Nature.A black hole and its bright accretion disk have been thought to form a quasar, the powerful light source at the center of some distant galaxies. Using a polarizing filter, the research...
Radio-telescope images have revealed previously-unseen galactic cannibalism -- a triggering event that leads to feeding frenzies by gigantic black holes at the cores of galaxies. Astronomers have long suspected that the extra-bright cores of spiral galaxies called Seyfert galaxies are powered by supermassive black holes consuming material. However, they could not see how the material is started on its journey toward the black hole.One leading theory said that Seyfert galaxies have been...
XMM-Newton has been surprised by a rare type of galaxy, from which it has detected a higher number of X-rays than thought possible. The observation gives new insight into the powerful processes shaping galaxies during their formation and evolution. Scientists working with XMM-Newton were looking into the furthest reaches of the universe, at celestial objects called quasars. These are vast cosmic engines that pump energy into their surroundings. It is thought an enormous black hole drives...
An ambitious study of active and inactive galaxies has given new insights into the complex interaction between super-massive black holes at the heart of Active Galactic Nuclei (AGN) and star formation in the surrounding galaxy. Results will be presented in a talk by Paul Westoby on Friday 4th April at the RAS National Astronomy Meeting in Belfast. Along with colleagues, Carole Mundell and Ivan Baldry from the Astrophysics Research Institute of Liverpool John Moores University, Westoby...
AUSTIN, Texas — A half-dozen hefty black holes hide out where they are least expected, in relatively skinny galaxies. The discovery implies galaxies don't need bulging bellies to harbor monstrous black holes. Until now, astronomers had thought central concentrations of stars called galactic bulges were required for black holes to grow. Our own Milky Way, like most spiral galaxies, has such a bulge. In many large galaxies, the bulge feeds binge eating by the black hole,...
An international team of astronomers using NASA's Swift satellite and the Japanese/U.S. Suzaku X-ray observatory has discovered a new class of active galactic nuclei (AGN).By now, you'd think that astronomers would have found all the different classes of AGN "” extraordinarily energetic cores of galaxies powered by accreting supermassive black holes. AGN such as quasars, blazars, and Seyfert galaxies are among the most luminous objects in our Universe, often pouring out the energy of...
Supermassive black holes have been discovered to grow more rapidly in young galaxy clusters, according to new results from NASA's Chandra X-ray Observatory. These "fast-track" supermassive black holes can have a big influence on the galaxies and clusters that they live in. Using Chandra, scientists surveyed a sample of clusters and counted the fraction of galaxies with rapidly growing supermassive black holes, known as active galactic nuclei (or AGN). The data show, for the first...
Latest Active galactic nucleus Reference Libraries
Seyfert Galaxy -- Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. The light from the central nucleus varies in less than a year, which implies that the emitting region must be less than one light year across. They are named for the astronomer Carl Seyfert, who studied them extensively in the 1940s. They are a subclass of active galactic nuclei....
Quasar -- A quasar (from quasi-stellar radio source) is an astronomical object that looks like a star in optical telescopes (i.e. it is a point source), but has a very high redshift. The general consensus is that this high redshift is cosmological, the result of Hubble's law and that their redshift indicates that they are typically very distant from Earth; we observe them as they were several billions of years ago. Since we can see them despite their distance, they must emit more...
Active Galaxy -- An active galaxy is a galaxy where a significant fraction of the energy output is not emitted from normal stellar populations or interstellar gas. This energy, depending on the active galaxy type, can be emitted across most of the electromagnetic spectrum, as infrared, radio waves, UV, X-ray and gamma rays. Frequently, the abbreviation AGN (Active Galactic Nuclei) is used, since most of the active galaxies emit most of their radiation from a narrow region in their...
Circinus Galaxy -- Resembling a swirling witch's cauldron of glowing vapors, the black hole-powered core of a nearby active galaxy appears in this colorful NASA Hubble Space Telescope image. The galaxy lies 13 million light-years away in the southern constellation Circinus. This galaxy is designated a type 2 Seyfert, a class of mostly spiral galaxies that have compact centers and are believed to contain massive black holes. Seyfert galaxies are themselves part of a larger class of objects...
