... ESA , NASA Explanation: The total mass within giant galaxy cluster CL0025+1654 , about 4.5 billion light-years away , produces a cosmic gravitational lens -- bending light as predicted by Einstein's theory of gravity and forming detectable images of even more distant background galaxies. Of course, the total cluster mass is the sum of the galaxies themselves, seen as ordinary luminous matter, plus the cluster's invisible dark matter whose nature remains unknown. ... Galaxies Away . ...

... 2014 May 5 . Galaxy Cluster Magnifies Distant Supernova . Image Credit: NASA , ESA , C. McCully ( Rutgers U. ) et al. Explanation: How do you calibrate a huge gravitational lens? ... A new calibration technique has been tested recently that consists of waiting for supernovas of a very specific type to occur behind a galaxy cluster, and then figuring out how much the cluster must have magnified these supernovas through gravitational lensing. ... About APOD | ...

Astronomy.com - A star cluster hides star clusters 4/2/08 11:35 AM News A star cluster hides star clusters Deep Hubble images of NGC 6397 reveal the most distant star clusters ever seen. Francis Reddy January 10, 2007 W hile exploring deep Hubble Space Telescope images of a globular star cluster called NGC 6397, astronomers stumbled on a distant background galaxy harboring hundreds of similar clusters. Each is so distant, it appears only as a faint point of light, even to Hubble's keen eye. ...

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... 2000, ApJ, 537, L49 . ... F. Palla . Invited Talk at the IAU Symposium 200 "The formation of binary stars" eds. R.D. Mathieu and H. Zinnecker (ASP Conf. Ser.) in press . Optical follow-up of ROSAT discovered candidate members of the open cluster Coma Berenices . ... 2000, A , in press . ... 2000, ApJ, in press . ... 2000, ApJ, in press (Sept. ... 2000, ApJ Lett., in press . ... Click to examine publications from other years . ... Star Formation Group . ... Arcetri Home Page . ...

... It is one of the most striking examples of gravitational lensing, where the gravitational field of a foreground galaxy bends and amplifies the light of a more distant background galaxy. In this image, the light from a distant galaxy, nearly 10 billion light-years away, has been warped into a nearly 90ТА arc of light in the galaxy cluster RCS2 032727-132623. The galaxy cluster lies 5 billion light-years away. ...

... In one situation, we can use light from quasars to probe the material between us and them because that light may pass through one or more galaxies or gas clouds on its way to us. The gas inside the galaxies or the intergalactic clouds acts then as a filter, absorbing selected wavelengths from the quasar light. ... Light from a quasar must pass through clouds of gas and even faint galaxies -- each leaving its imprint on the light -- before we receive it here on Earth. ... Gravitational lensing . ...

Galactic Wind Shells and High Redshift Radio Galaxies . ... M.Krause . Astronomy & Astrophysics, v.436, 845-851 . Very Light Jets II: Bipolar large scale simulations in King atmospheres [small version] . ... Simulations of Astrophysical Jets in Dense Environments . M.Krause, V.Gaibler & M.Camenzind . in: High Performance Computing in Science and Engeneering '05 eds.: E.Krause, W.J ger & M.Resch. ... M.Krause & M.Camenzind . ... Martin Krause & Paul Alexander . ... Martin Krause . ...

Title: A New Model of the Gravitational Lens 0957+561 and a Limit on the Hubble Constant . Authors: Norman A. Grogin , Ramesh Narayan (Harvard Univ.) ... Title: ROSAT/PSPC observation of the distant cluster CL0939+472 . ... Title: Interaction in the Bimodal Galaxy Cluster A3528 . ... Title: Cosmological Implications of Galaxy Cluster Evolution . ... Title: Galaxy Cluster Virial Masses and Omega . ... Matches 201 to 222 from a total of 222 matches for the search pattern galaxy cluster . ...

... Home Lectures Lecture Series 2011-2012 Lecture Series 2011-2012 ? тАЬA Ray of Light in a Sea of Dark (Matter)тАЭ ? Charles Keeton . ... Charles Keeton , associate professor of physics and astronomy at Rutgers University and faculty director of the Aresty Research Center for Undergraduates , will speak to the AAA Friday, March 2, on тАЬA Ray of Light in a Sea of Dark (Matter).тАЭ The free public lecture begins at 6:15 p.m. in the Kaufmann Theater of the€а American Museum of Natural History . ...

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DARK MATTER IN THE UNIVERSE Paul J. Green UNSEEN MASS: Astronomers studying the motions of stars and galaxies throughout the universe have long noticed a strange discrepancy. Stars move around galaxies as if pulled by ten times the matter that we can see. ... GRAVITATIONAL LENSING: Since dark matter by definition cannot be directly observed, several recent searches have instead exploited the predicted gravitational effects of its mass on the observed light from nearby stars. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Our Galaxy . ... Other Galaxies . ... Space Flight . ... Posted on October 4, 2010 | 1 Comment Gorgeous! ... Continue Reading.. ... Posted on September 24, 2010 | ... 1 Comment That amazing instrument, the Hubble Space Telescope (HST), has just celebrated its twentieth anniversary since it was placed in orbit. ... No Comments Dark matter and its part in the evolution of the Universe is revealed by new data collected by the Hubble Space Telescope. ...

... The Butcher-Oemler Effect Blue Fraction, fB Redshift , z The Butcher-Oemler Effect Blue Fraction, fB Abell 370 Redshift , z Abell 370 a galaxy cluster at z = 0.37 Abell 370 , a galaxy cluster at z = 0.37 large galaxy cluster of order same size as Coma similar cluster velocity dispersion and X-ray gas temperature GMRT ~34 hours on OII] Star Formation Rate Average all 168 [OII] emission galaxies line from Bell 2003 Radio Continuum vs. ...

... Bad Astronomy . Misconceptions . ... Bad Astronomy : "We're light years more advanced than our competition!" ... Even the closest astronomical object, the Moon, is 400,000 kilometers away! ... A beam of light will travel 9,500,000,000,000 kilometers in one year. This distance is defined as a light year ; the distance light travels in a year. ... This is another example of Bad Astronomy; like a light year, a parsec is a unit of distance, not time (to be specific, it equals 3.26 light years) . ...

... ATNF Home . About ATNF . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Australian Square Kilometre Array Pathfinder . Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . Mopra radio telescope . ... Australia Telescope Online Archive (ATOA) . ... Visiting Parkes radio telescope . Visiting Australia Telescope Compact Array . ... Parkes radio telescope webcam . ...

... self-absorption - the absorption of light shining on an object by a process similar to that which produced the light originally; if a cloud emits less light than it absorbs from other clouds behind it, this net loss of light, termed self-absorption , causes the foreground cloud to appear darker than the background field (the term is from spectroscopy, where small absorption dips sometimes occur in larger emission lines, making the latter look as if it is absorbing part of itself) . ... HISA Main ...

This animation shows a galaxy cluster with two mass concentrations (the pink shading indicates the projected mass density) lensing a background field of faint blue galaxies. ... Inside the Einstein ring radius one has radial arcs, and right in the center of the cluster there are demagnified images. The highest magnifications occur at the Einstein ring radius, giving the large tangential arcs. ... Abell 2218 and CL2244-02 are clusters with tangential arcs. ... Tutorial : Part 1 | Part 2 | ...

... Compact Binaries . ... Unlike the Sun, most stars in our Galaxy orbit another star: these systems are called binary stars. Generally it takes many years for the two stars to orbit around each other. ... These binaries are interesting for many reasons. One is that they are predicted to emit lots of gravitational waves. ... Over time as gravitational waves are emitted, the time taken for the two stars to orbit one another changes by a small but measurable amount. ...

... Spacecraft . 29b. Satellites looking down . ... 29e. Explorers of distant space . ... The Hubble orbiting telescope. ... The Hubble telescope , in low Earth orbit, overcomes such limitations, in the visible range and in part of the UV. ... So fruitful was this observation that a second "deep field" exposure of such length, near the southern pole of the heavens, was recently conducted. ... Some satellites specialize in observing the Sun, such as the Japanese Yohkoh and NASA's SOHO . ...