Re: SDSS-II supernova survey explodes with new findings (Forwarded)

This is a WELCOME FEATURE that fits in to my PROJECTION: COSMIC POT
ENERGY CONCEPT that covers one Universe- see STSCI-SYMP-May 2003.
Scientists should not mix-up with COSMIC EXPANSION- beyond One Universe
Concept.
see Carnegie Observatories-Cosmology Structures-New Modelling -Jan 2003
Centennial Symp-3.. This projection is for COSMOS- an advanced
concept for STRING THEORY GROUPS.
Regards
Vidyardhi Nanduri
Cosmology for World Peace
SEARCH GOOGLE:Cosmology Vedas

Andrew Yee wrote:
> Sloan Digital Sky Survey
>
> CONTACTS:
> Joshua Frieman
> Fermi National Accelerator Laboratory (Fermilab)
> At Fermilab: 630-840-2226; University of Chicago: 773-702-7971
>
> David Weinberg
> Scientific Spokesperson, The Sloan Digital Sky Survey
> At AAS: 614-406-6243
>
> Gary S. Ruderman
> Public Information Officer, The Sloan Digital Sky Survey
> 312-320-4794
>
> January 12, 2006
>
> SDSS-II SUPERNOVA SURVEY EXPLODES WITH NEW FINDINGS
>
> WASHINGTON DC -- The population of supernovae -- exploding stars in
> distant galaxies -- has exploded here on Earth with an unprecedented
> number of new discoveries logged in just 90 days by the Sloan Digital
> Sky Survey (SDSS-II).
>
> The Sloan Supernova Survey today reported the discovery of 139 new Type
> Ia supernovae during its first campaign last fall.
>
> These supernovae will be used to provide more precise constraints on the
> nature of the mysterious Dark Energy that is causing the expansion of
> the Universe to speed up. They will also yield greater understanding of
> supernovae as standard distance signposts (aka standard candles or
> standard light bulbs) in the Universe.
>
> "Finding so many supernovae in such a short time is unprecedented,
> because the SDSS probes a larger volume of space than previous surveys,"
> explained supernova team co-leader Joshua Frieman of the Fermi National
> Accelerator Laboratory (Fermilab) and the University of Chicago. The
> results were made public during a session on Supernovae and Cosmology at
> the American Astronomical Society's winter meeting in Washington, DC.
>
> To find supernovae, the team used the dedicated SDSS-II 2.5-meter
> telescope at the Apache Point Observatory in New Mexico. Its
> 120-megapixel CCD camera is used to scan the same part of the sky
> roughly every other night over a three-month period, searching for
> supernovae that explode in any of the three million galaxies it sees.
> Comparing images taken on different nights, astronomers can look for
> objects that have brightened over time -- potential supernovae. Shortly
> after it explodes, a supernova becomes as bright as an entire galaxy, so
> it can be seen across vast cosmic distances.
>
> "An advantage of the SDSS is that it carries out nearly simultaneous
> imaging in five different portions of the optical spectrum, providing
> measurements of the colors as well as the brightness of objects,"
> explained Masao Sako of Stanford University. Using these colors, Sako
> and other members of the SDSS-II supernova team were able to zero in
> with very high efficiency on the prized Type Ia supernovae, the most
> precise standard candles.
>
> The most promising Type Ia candidates were targeted for follow-up
> spectroscopy on a variety of other telescopes, including the
> Astrophysical Research Consortium's 3.5-meter telescope, the
> Hobby-Eberly 9.2-meter telescope in Texas, the William Herschel
> 4.2-meter telescope in the Canary Islands, Japan's Subaru 8.2-meter
> telescope, Keck 10-meter telescope in Hawaii and the MDM Hiltner
> 2.4-meter telescope in Arizona.
>
> "Follow up observations that measure the spectrum of the supernova are
> critical," explained team member John Marriner of Fermilab. "First, they
> confirm that the candidate is a Type Ia rather than some other kind of
> supernova, and second, they determine the velocity at which it is
> receding from the Earth." That recession velocity is caused by the
> expansion of the Universe; by combining the brightnesses and recession
> velocities of large numbers of supernovae, astronomers can unravel the
> history of the cosmic expansion rate.
>
> Since supernovae are bright only for a few weeks, the candidates must be
> identified quickly so that their spectra can be measured before they
> fade. A cluster of 10 dual-processor computers at the observatory
> automatically processes the data and looks for differences between the
> images just taken and those of the same part of the sky in previous years.
>
> "A full night of data collection with the telescope yields about 2,400
> images, each one roughly equivalent to the image in a four-megapixel
> digital camera. We process these images with our computers in about 20
> hours," explained supernova researcher Richard Kessler of the University
> of Chicago. "This accumulation of 70 gigabytes of images each night is
> equal to more than 100 CDs or 15 DVDs."
>
> The new supernova sample also bridges the gap between the nearby
> supernovae found in local surveys and the very distant objects found by
> deeper surveys of much smaller areas. "The combination of a 2.5-meter
> aperture and a very large field of view makes the SDSS telescope ideal
> for finding intermediate distance supernovae, about 1 to 3 billion light
> years from Earth," explained Jon Holtzman of New Mexico State
> University. "Only a handful of supernovae at these distances had been
> found previously."
>
> "All of the well-known results on the accelerating universe have so far
> come from comparing nearby supernovae to distant supernovae that were
> discovered and measured in different kinds of surveys," added Frieman.
> "The SDSS-II survey fills in the missing rungs on the ladder."
>
> The race to improve the quality of supernova samples over a range of
> distances is heating up.
>
> "The Sloan Supernova Legacy Survey and the ESSENCE survey are compiling
> more distant samples that will include hundreds of supernovae by the
> time they each finish a few years from now," noted Craig Hogan of the
> University of Washington. "Combining the SDSS results with these deeper
> surveys will probe the cosmic expansion and the nature of the dark
> energy with greater precision." (ESSENCE is a five-year supernova survey
> designed to constrain the physics of Dark Energy,
> http://www.ctio.noao.edu/wproject)
>
> The SDSS researchers are also looking forward to some surprises in the
> "astronomical zoo."
>
> "We focused on the type Ia supernovae this season, because of the
> exciting cosmology applications, but the SDSS gives us a unique tool to
> study unusual supernova types," noted Stanford University's Roger
> Romani. "We have shown that we can sift through hundreds of new
> supernovae to select the rare gems. With a survey volume this large,
> these rarities turn up frequently enough to allow serious investigation
> of their place in the astronomical zoo."
>
> SUPERNOVAE BACKGROUND
>
> Type Ia Supernovae are formed when white dwarf stars -- the remnants of
> stars similar to our Sun -- collapse inward and blow up like an atomic
> bomb in brief but intense bursts of energy. The white dwarf accumulates
> gas from a companion star until it explodes, spewing gas and particles
> of iron, nickel and cobalt. The brightness of the Type Ia light peaks
> about three weeks after the explosion and declines over a period of months.
>
> In the early 1990's, astronomers found that type Ia supernovae could be
> used to study cosmological distances because they appear to be accurate
> standard candles. In 1998, two research groups studying distant type Ia
> supernovae found that they were fainter than would be expected if the
> expansion of the Universe were slowing down due to the attractive pull
> of gravity. Instead, the evidence, which has since been confirmed by
> other cosmological observations, pointed to a speed-up of the Universe
> that began a few billion years ago. The cause of this acceleration is
> thought to be a bizarre form of energy, dubbed dark energy, which
> permeates the Universe and acts as a source of gravitational repulsion.
>
> Information about the newly discovered SDSS-II supernovae has been
> distributed to the astronomical community via the International
> Astronomical Union circulars and the Central Bureau for Electronic
> Telegrams. These listings of supernova discovery dates, positions,
> magnitudes, and list of co-authors helps the community perform follow-up
> research. The public listing of confirmed supernovae is at
> http://sdssdp47.fnal.gov/sdsssn/snlist.php
>
> The Sloan Supernova Survey is one of three research and discovery
> components of The Sloan Digital Sky Survey (II), which will run through
> mid-2008.
>
> AUTHORS:
>
> * J. Barentine, Apache Point Observatory (APO)
> * B. Bassett, University of Portsmouth (UP)
> * A. Becker, University of Washington
> * R. Bender, University of Munich (UM)
> * M. Bremer, University of Bristol
> * H. Brewington, APO
> * F. DeJongh, Fermilab
> * J. Dembicky, APO
> * D. L. DePoy, Ohio State University (OSU)
> * B. Dilday, University of Chicago (UC)
> * M. Doi, University of Tokyo (Tokyo)
> * E. Elson, South African Astronomical Observatory (SAAO)
> * J. Frieman, Fermilab and UC
> * P. Garnavich, University of Notre Dame
> * M. Harvanek, APO
> * T. Gueth and J. Holtzman, New Mexico State University
> * U. Hopp, UM
> * W. Kollatschny, Goettingen University
> * K. Konishi, Tokyo
> * J. Krzesinski, APO
> * H. Lampeitl, Space Telescope Science Institute (STScI)
> * R. Kessler, UC
> * B. Ketzeback, D. Long, O. Malanushenko, V. Malanushenko, APO
> * J. Marriner, Fermilab
> * J. L. Marshall, OSU
> * R. McMillan, APO
> * G. Miknaitis, Fermilab
> * T. Morokuma, Tokyo
> * R. Nichol, UP
> * K. Pan, APO
> * J.L. Prieto, OSU
> * M. Richmond, Rochester Institute of Technology
> * A. Riess, STScI
> * R. Romani and M. Sako, Stanford University (SU)
> * D. Schneider, Penn State University
> * M. Smith, UP
> * S. Snedden, APO
> * M. Subbarao, UC and Adler Planetarium
> * N. Takanashi and K. Tokita, Tokyo
> * K. van der Heyden, SAAO
> * J. C. Wheeler, University of Texas
> * N. Yasuda, Tokyo
>
> IMAGE CAPTION:
> [(left) http://www.sdss.org/news/releases/20060112.SN.1.png (80KB)
> (Right) http://www.sdss.org/news/releases/20060112.SN.2.png (121KB)]
> SDSS-II images of a Type Ia supernova on the rise (left) and near
> maximum light (right).
> CREDIT - SDSS-II Collaboration

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