Quantcast
Last updated on April 17, 2014 at 14:57 EDT

Latest Weak gravitational lensing Stories

43b1ea9ecc650504b0ee9917e84de639
2010-12-06 13:45:00

Cosmologists have come up with a new way to solve their problems. They are inviting scientists, including those from totally unrelated fields, to participate in a grand competition. The idea is to spur outside interest in one of cosmology's trickiest problems -- measuring the invisible dark matter and dark energy that permeate our universe. The results will help in the development of new space missions, designed to answer fundamental questions about the history and fate of our universe....

0c79484a475e64b08c7ed5b5a740ec921
2010-11-22 06:50:00

Submillimeter observatories penetrate cold, dusty galaxies to see stars forming in the primeval past A chance alignment of galaxies, recently observed by a space observatory, presents the perfect opportunity for studying star-forming galaxies billions of light-years away. For decades, astronomers have used Einstein's concept of a "gravitational lens" to study the magnified images of distant objects.  A lensing effect occurs when a massive object, such as a galaxy, is located exactly...

ab73a6bf9d0947941c2a6664c16de0701
2010-11-11 12:50:00

Astronomers using NASA's Hubble Space Telescope took advantage of a giant cosmic magnifying glass to create one of the sharpest and most detailed maps of dark matter in the universe. Dark matter is an invisible and unknown substance that makes up the bulk of the universe's mass. The new dark matter observations may yield new insights into the role of dark energy in the universe's early formative years. The result suggests that galaxy clusters may have formed earlier than expected, before the...

1ff02c5f2a78a35cc9b26a407f0b990b1
2010-05-05 09:05:00

A new wide-field image released today by ESO displays many thousands of distant galaxies, and more particularly a large group belonging to the massive galaxy cluster known as Abell 315. As crowded as it may appear, this assembly of galaxies is only the proverbial "tip of the iceberg", as Abell 315 "” like most galaxy clusters "” is dominated by dark matter. The huge mass of this cluster deflects light from background galaxies, distorting their observed shapes slightly. When...

9b1dc5ec9ca87876b5f69cb67a582a6b1
2010-04-21 14:45:00

Narrower constraints from the newest analysis aren't quite narrow enough The international Supernova Cosmology Project (SCP), based at the U.S. Department of Energy's Lawrence Berkeley National Laboratory, has announced the Union2 compilation of hundreds of Type Ia supernovae, the largest collection ever of high-quality data from numerous surveys. Analysis of the new compilation significantly narrows the possible values that dark energy might take"”but not enough to decide among...

06085b6db9a6a6e2518b778798490e9d1
2010-03-25 07:35:00

A group of astronomers [1], led by Tim Schrabback of the Leiden Observatory, conducted an intensive study of over 446 000 galaxies within the COSMOS field, the result of the largest survey ever conducted with Hubble. In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the same part of the Universe using the Advanced Camera for Surveys (ACS) onboard Hubble. It took nearly 1000 hours of observations. In addition to the Hubble data, researchers used redshift [2]...

82254273e52c7c95420fc7866639524e1
2010-01-20 12:20:00

Observations of faint and distant galaxy groups made with the European Space Agency's XMM-Newton observatory have been used to probe the evolution of dark matter. The results of the study are reported in the January 20 issue of The Astrophysical Journal. Dark matter is a mysterious, invisible constituent of the Universe which only reveals itself through its gravitational influence. Understanding its nature is one of the key open questions in modern cosmology. In one of the approaches used to...

868849ad034d367cd193a6de70d7fdf21
2010-01-20 09:27:32

Weak gravitational lensing is a uniquely promising way to learn how much dark matter there is in the Universe and how its distribution has evolved since the distant past. New work by a team led by a cosmologist from the U.S. Department of Energy's Lawrence Berkeley National Laboratory has made major progress in extending the use of gravitational lensing to the study of much older and smaller structures than was previously possible. Until recently, weak lensing had been limited to calculating...

664e28f8cdf55553f2e8f473cd13251c
2009-08-07 09:30:00

Several ways have been proposed to examine dark energy, in hopes of finding out just what it is. One of them, "supernovae" for short, certainly works: it's how dark energy was discovered in the first place. Other independent techniques, such as weak gravitational lensing and baryon acoustic oscillation, also promise great power but are as yet unproven.These three techniques all have a share of the proposed Joint Dark Energy Mission (JDEM), a satellite design managed by NASA with the...

3d8caad10cffe08b1f717809a04eab441
2008-09-20 09:00:00

A Unique Way to Measure Dark Energy With Galaxies and Quasars The Sloan Digital Sky Survey (SDSS) uses a 2.5-meter telescope with a wider field of view than any other large telescope, located on a mountaintop in New Mexico called Apache Point and devoted solely to mapping the universe. We now know that some three-quarters of the universe consists of dark energy, whose very existence was unsuspected when telescope construction began in 1994 and still controversial when the first Sloan survey...


Latest Weak gravitational lensing Reference Libraries

45_ea0b4f3c063ef1aeec4ef6fed79a5d9d
2010-09-07 17:31:13

The Bullet Cluster is made up of two colliding clusters galaxies. According to a 2006 study, the Bullet Cluster also shows the best evidence for the existence of Dark Matter. From observations of galaxy cluster collisions it has been found that many show displacement between their center of visible matter and their gravitational potential. Each component, stars, gas, and dark matter, within a cluster pair behaves differently during a collision allowing for each to be studied separately....

6_fec4ca0e97baf4ce0833c41b1e6be5e62
2004-10-19 04:45:41

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...

More Articles (2 articles) »