|
|
|
|
|
Hubble captures a 'five-star' rated gravitational lens HUBBLE EUROPEAN SPACE AGENCY INFORMATION CENTRE NEWS RELEASE Posted: May 22, 2006 The Hubble Space Telescope has captured the first-ever picture of a distant quasar lensed into five images. In addition, the image holds a treasure of lensed galaxies and even a supernova.
Although other multiply lensed quasars have been seen before this newly observed ³quintuple quasar² is the only case so far in which multiple quasar images are produced by an entire galaxy cluster acting as a gravitational lens. The background quasar is the brilliant core of a galaxy. It is powered by a black hole, which is devouring gas and dust and creating a gusher of light in the process. When the quasar's light passes through the gravity field of the galaxy cluster that lies between us and the quasar, the light is bent by the space-warping gravity field in such a way that five separate images of the object are produced surrounding the cluster's centre. The fifth quasar image is embedded to the right of the core of the central galaxy in the cluster. The cluster also creates a cobweb of images of other distant galaxies gravitationally lensed into arcs. The galaxy cluster creating the lens is known as SDSS J1004+4112 and was discovered as part of the Sloan Digital Sky Survey. It is one of the more distant clusters known (seven billion light-years, redshift z=0.68), and is seen when the Universe was half its present age. Gravitational lensing occurs for extremely concentrated masses like the cores of galaxies or galaxy clusters. Their strong gravity warps the surrounding space, and light travelling through that warped space bends its direction. Multiple images of a distant light source may be seen, each taking a different path through the warped space.
The galaxy hosting the background quasar is at a distance of 10 billion light years (at redshift 1.74). The quasar host galaxy can be seen in the image as faint red arcs. This is the most highly magnified quasar host galaxy ever seen. The Hubble picture also shows a large number of stretched arcs that are more distant galaxies lying behind the cluster, each of which is split into multiple distorted images. The most distant galaxy identified and confirmed so far is 12 billion light years away (a redshift of 3.33, corresponding to only 1.8 billion years after the Big Bang). By comparing this image to a picture of the cluster obtained with Hubble a year earlier, the researchers discovered a rare event - a supernova exploding in one of the cluster galaxies. This supernova exploded seven billion years ago, and the data, together with other supernova observations, are being used to try to reconstruct how the Universe was enriched by heavy elements through these explosions. |
|
|
|
 |
||||||||||||||||||||||
As night fell over Kennedy Space Center on May 19, space shuttle Discovery reached launch pad 39B to complete the slow journey from the Vehicle Assembly Building. Discovery will be traveling much faster in a few weeks when it blasts off to the International Space Station.
The November 1985 flight of space shuttle Atlantis began with a rare nighttime blastoff. The seven-member crew, including a Mexican payload specialist, spent a week in orbit deploying three communications satellites for Australia, Mexico and the U.S. And a pair of high-visibility spacewalks were performed to demonstrate techniques for building large structures in space. The crew narrates the highlights of STS-61B in this post-flight crew film presentation.
Eight astronauts, the largest crew in history, spent a week in space during the fall of 1985 aboard shuttle Challenger for mission STS-61A, the first flight dedicated to the German Spacelab. The crew worked in the Spacelab D-1 laboratory conducting a range of experiments, including a quick-moving sled that traveled along tracks in the module. A small satellite was ejected from a canister in the payload bay as well. The astronauts narrate the highlights of the mission in this post-flight film.
Perched atop a trailer-like transporter, space shuttle Discovery was moved May 12 from its hangar to the 52-story Vehicle Assembly Building for mating to its external fuel tank and twin solid rocket boosters in preparation for the STS-121 mission.
The U.S. Astronaut Hall of Fame inducted its 2006 class of shuttle commanders Henry Hartsfield, Brewster Shaw and Charles Bolden. The ceremony was held inside the Saturn 5 museum at Kennedy Space Center.
NASA's twin Solar Terrestrial Relations Observatory satellites (STEREO) arrive via truck at the Astrotech processing facility outside Kennedy Space Center for final pre-launch testing and preparations. They will be launched this summer aboard a Boeing Delta 2 rocket to provide the first 3-D "stereo" views of the sun and solar wind. 
Space shuttle Challenger was transformed into an orbiting observatory to study the sun, stars and space environment during the Spacelab 2 mission in the summer of 1985. But getting into space wasn't easy. The shuttle suffered an engine shutdown on the launch pad, then during ascent two weeks later lost one of its three main engines. It marked the first Abort To Orbit in shuttle history. In this post-flight film, the crew of STS-51F narrates highlights of the mission that includes tests using a small plasma-monitoring satellite was launched from Challenger's robot arm.
A seven-person crew featuring payload specialists from France and Saudi Arabia flew aboard the June 1985 mission of space shuttle Discovery. They narrate the highlights of STS-51G in this post-flight film. Three communications satellites -- for Mexico, the Arab countries and the U.S. -- were launched from the payload bay. And the SPARTAN 1 astrophysics spacecraft was deployed from the shuttle's robot arm for a two-day freeflight to make its science observations before being retrieved and returned to Earth.
