Current Science at NOAO

A Shear Way to Find Dark Matter and Transients, Too!

Tony Tyson, Bell Labs, and Ian Dell'Antonio, NOAO/National Science Foundation

A 5'x5' section of one of the fields (imaged at half depth) is shown here to illustrate the level of detail available in the data.

March, 2000  |  Astronomer Tony Tyson and a team of some twenty investigators worldwide are mapping the large-scale structure of matter in the Universe using the Mosaic CCD imagers at the National Science Foundation's Blanco and Mayall 4-m telescopes at the Cerro Tololo InterAmerican Observatory and the Kitt Peak National Observatory. This "Deep Lens Survey" will take five years to complete.

Images of distant galaxies are distorted, or sheared, by the gravity of intervening matter, and the Deep Lens Survey will measure this shear. These observations are sensitive to all forms of clumped mass and will yield maps of matter in the Universe with resolution of 1' in the plane of the sky and as a function of distance. These maps will measure the change in large-scale structure from z=1 to the present epoch. Current theories of structure formation predict that mass in the low-redshift universe has a filamentary/sheetlike structure. The observations will be able to detect these structures if they are present.

The deep combined data images and catalogs will be released to the community as they are completed. The Deep Lens Survey will also detect variable stars and galaxies, including supernovae, in the observed fields. Observations will be spread over four runs and two years, so that objects with varying brightness can be identified. Optical transient events and supernova candidates will be announced as soon as they are discovered. Moving-objects (asteroids, Kuiper Belt Objects, and comets) will be also be made available as they are found.

The survey fields will be imaged in several colors. The faintest observations will be done in red light, allowing detection of galaxies more than a billion times fainter than the human eye can see. Images in other colors won't go as faint and mainly provide estimates of redshift based on color. A 5'x5' section of one of the fields (imaged at half depth) is shown above to illustrate the level of detail available in the data.

For more information see:
   NOAO Newsletter
   Deep Lens Survey at Bell Labs
   Deep Lens Survey at the University of Washington

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