Latest Accretion disc Stories
Gamma-ray beams seen in the Milky Way's central black hole suggest that the galaxy's center was much more active in the past, according to new research.
Black holes that grow to masses billions of times greater than that of our sun most likely reached those sizes by consuming objects from multiple locations at the same time.
By studying the X-rays emitted when superheated gases plunge into distant and massive black holes, astrophysicists have provided an important test of a long-standing theory that describes the extreme physics occurring when matter spirals into these massive objects.
Two UK astronomers have found that the giant black holes in the center of galaxies are on average spinning faster than at any time in the history of the Universe.
Astrophysicists use computer simulations to gain new insights on star formation.
Using two of the worldâ€™s largest telescopes, an international team of astronomers have found evidence of a collision between galaxies driving intense activity in a highly luminous quasar.
Up to now, primitive black holes, which occupy the cores of active galaxies and were around as far back as the early days of the universe, only existed in astronomerâ€™s models.
Studies of one of the galaxy's most active black-hole binaries reveal a dramatic change that will help scientists better understand how these systems expel fast-moving particle jets.
The constellation of Orion is a hotbed of massive star formation, most prominently in the Great Nebula that sits in Orion's sword.
New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce.
Cosmogony -- Cosmogony is the study of the origins of celestial objects. It is most commonly used to refer to the study of the origin of the solar system. Currently, the most widely accepted theory is that the solar system was formed roughly 5 billion years ago with the collapse of a nebula of gas and dust, likely caused by shock waves generated by a nearby supernova. The solar system would have formed as a member of a star cluster, now long-since dispersed throughout the Milky Way over...
X-ray Burster -- X-ray bursters are a class of binary stars which are luminous in X-rays. They contain a neutron star and a low-mass companion star. The companion fills its Roche lobe and therefore the neutron star is accreting matter from it. The inflowing gas forms an accretion disk around the neutron star. Sometimes X-ray bursters show a sudden increase in their X-ray luminosity, called X-ray burst. All properties of the X-ray bursts can be explained assuming that they result from...
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....
Microquasar -- Microquasars are smaller cousins of quasars. They are named after quasars, as they have some common characteristics: strong and variable radio emission often seen as radio jets, and an accretion disk surrounding a black hole. In quasars, the black hole is supermassive (millions of solar masses) as in microquasars, the black hole mass is a few solar masses. In microquasars, the accreted mass comes from a normal star and the accretion disk is very luminous in optical regions...
Accretion Disk -- An accretion disk is a structure formed by material falling into a gravitational source. Conservation of angular momentum requires that, as a large cloud of material collapses inward, any small rotation it may have will increase. Centrifugal force causes the rotating cloud to collapse into a disk, and tidal effects will tend to align this disk's rotation with the rotation of the gravitational source in the center. Friction between the particles of the disk generates heat...
- One who brings meat to the table; hence, in some countries, the official title of the grand master or steward of the king's or a nobleman's household.