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| The Synthesis Of Large Radio Telescopes |
| 07.09.09 (10:47 am) [edit] |
| Astronomers using the NASA Hubble Space Telescope's Advanced Camera for Surveys (ACS) have found two supernovae that exploded so long ago they provide new clues about the accelerating universe and its mysterious "dark energy. With the Hubble Telescope, we can now see back to the epoch when stars in young galaxies began to shine in significant numbers, concluding the cosmic 'dark ages' about 13 billion years ago," said Haojing Yan, a Ph D graduate student at Arizona State University (ASU) unscrambled . Looking farther away into the universe (and, because of the distances involved, further into the past), they've seen evidence that gravity was at that time slowing the expansion of the universe. They've attributed this accelerating expansion to a mysterious factor known as dark energy that is believed to permeate the universe. When comparing the Hubble and Chandra fields, astronomers also found that active black holes in distant, relatively small galaxies were rarer than expected. This makes them reliable objects for calibrating vast unscrambled distances. The farther one exploded so long ago the universe may still have been decelerating under its own gravity. The supernovae were found when ACS unscrambled members Daniel Magee (University of California at Santa Cruz) and Zlatan Buy Ambien For Cheap (Johns Hopkins University) compared Ambien From United States Overnight Without Prescription Hubble images of the same patch of sky with new ACS images and identified the two supernovae. Astronomers have very little data, Buy Ambien (COD) on the period of transition between these two phases, when the repulsion produced by dark energy began to surpass the tug of gravity. Follow-up observations were then conducted with ACS and other Hubble instruments to get a detailed fix on their intensities and distances from Earth. This is also consistent with the idea unscrambled the sizes of galaxies match hand-in-glove to a certain fraction of the sizes of their dark-matter halos. Continued studies of supernovae will allow us to uncover the full history of the universal expansion," Blakeslee says. The Chandra results are found in papers led by Koekemoer and Stefano Cristiani of the Trieste Astronomical Observatory. Hubble's findings came from papers led by Giavalisco, Mark Dickinson, and unscrambled Ferguson of the STScI. In 2001 Hubble astronomers found a supernova even farther away. Website For Ambien filtering effects of interstellar dust Purchase Ambien C.O.D. lead to misinterpretation of the cosmic distances unless carefully taken into account. We have enough data on the new supernovae to constrain both their distance and the amount of Prescription Drug - Ambien Ambien Cheap Overnight says Blakeslee. Either they are the most distant black holes ever detected, or they are less distant black holes that are the most dust enshrouded known, a surprising result as well. According to the Johns Hopkins astronomers, the supernovae they discovered will be just the first of Cheap Ambien Online (COD) to be identified with the ACS. We're trying to fill in a blank region where the universe's rate of expansion switched from deceleration due to gravity to acceleration due to the repulsive force of dark energy," says John Blakeslee, an associate ACS research scientist at Johns Hopkins University, Baltimore, Md., and lead author of a new paper due out in the June Astrophysical Journal. These and other results from the GOODS project will be published in a special issue of the Astrophysical Journal Letters, entirely devoted to the team's results. Information from studies of Type Ia supernovae confronted astronomers about five years ago with the stunning, unexpected revelation that galaxies appeared to be moving away from each other at an Ambien Without Rx speed. The ACS can then dissect their unscrambled (by spectroscopy) to measure their distances, study how they fade, and confirm that they are a special type of exploding star that are reliable distance indicators. This may be due to the effects of early generations of massive stars that exploded as supernovae, evacuating galactic gas and thus reducing unscrambled supply of gas needed to feed a supermassive black hole. The supernovae are approximately 5 and 8 billion light-years from Earth. It offered the first evidence the expanding universe was once decelerating. |