Provided by Richard Hook, ESO Quasars are galaxies with very active supermassive black holes at their centers. These black holes are surrounded by spinning discs of extremely hot material that is often spewed out in long jets along their axes...
Latest Quasar Stories
Approximately 12 million light years from Earth is a galaxy called NGC 7793, and just on the outskirts of this galaxy is a black hole, designated P13, which new research has revealed is ingesting a weight equivalent to 100 billion billion hot dogs every minute.
New work from Carnegie’s Hubble Fellow Yue Shen and Luis Ho of the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University solves a quasar mystery that astronomers have been puzzling over for 20 years.
New research from UCL shows we will soon uncover the origin of the ultraviolet light that bathes the cosmos, helping scientists understand how galaxies were built.
Several processes typically limit how quickly black holes can grow, so how did those located at the ends of the universe come to have masses equal to several billion suns?
The amount of light originating from known populations of galaxies and quasars is far less than the amount required to explain the amount of hydrogen that helps bridge empty spaces between galaxies, according to research appearing in a recent edition of The Astrophysical Journal Letters.
Astronomers investigating behavior of the universe shortly after the Big Bang have made a surprising discovery: the properties of the early universe are determined by the smallest galaxies.
WASHINGTON, June 19, 2014 /PRNewswire-USNewswire/ -- An international team of astronomers, using data from several NASA and European Space Agency (ESA) space observatories, has discovered unexpected
Astronomers using the NASA Fermi Gamma-ray Space Telescope to study what they thought were two different classes of black-hole-powered galaxies known as blazars now believe that they may be one and the same.
Caltech astronomers have taken unprecedented images of the intergalactic medium (IGM)—the diffuse gas that connects galaxies throughout the universe—with the Cosmic Web Imager, an instrument designed and built at Caltech.
An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history.
Large-Scale Structure of the Cosmos -- Stars are organised into galaxies which in turn appear to form clusters and superclusters, separated by voids. Prior to 1989 it was commonly assumed that the superclusters were the largest structures in existence, and that they were distributed more-or-less uniformly throughout the universe in every direction. However, in 1989, Margaret Geller and John Huchra discovered the "Great Wall", a sheet of galaxies more than 500 million light years long...
Supermassive Black Hole -- A Supermassive black hole is a black hole with a mass in the range of millions or billions solar masses. A supermassive black hole has some interesting properties differing from his low-mass cousins: -- The average density of a supermassive black hole can be very low, and actually can be lower than water's density. This happens because the black hole diameter increases linearly with mass, and consequently density drops much faster. -- Strong tidal...
Redshift -- Redshift is the phenomenon that the frequency of light when observed, under certain circumstances, can be lower than the frequency of light when it was emitted at the source. This usually occurs when the source moves away from the observer, as in the Doppler effect. More specifically, the term redshift is used for the observation that the spectrum of light emitted by distant galaxies is shifted to lower frequencies (towards the red end of the spectrum, hence the name) when...
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...
Gravitational Lens -- A gravitational lens is formed when the light from a very distant, bright object (such as a quasar) is "bent" around a massive object (such as a massive galaxy) between the bright object and the viewer. The process is known as gravitational lensing, and was one of the predictions made by Einstein's general relativity. Description In a gravitational lens, the gravity from the massive object bends light as a lens might. As a result, the path of the light from a...
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