NOAO >   Observing Info >   Approved Programs >   2003A-0256

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Proposal Information for 2003A-0256


PI: Mukremin Kilic, The University of Texas at Austin, kilic@bullwinkle.as.utexas.edu
Address: Astronomy Department, 1 University Station, C1400, Austin, TX 78712, USA

CoI: Don E. Winget, U. Texas, McDonald Obs.
CoI: Ted von Hippel, U. Texas, McDonald Obs.
CoI: Chuck F. Claver, Kitt Peak, NOAO

Title: Identification of Cool White Dwarfs in the NOAO Deep Wide-Field Survey: Finishing the Northern Field

Abstract: We propose to continue our search for the cool white dwarfs belonging to the Galactic disk by extending the NOAO deep wide-field survey (DWFS). This search will identify an enormous number of new white dwarfs which will improve the white dwarf luminosity function (WDLF) by a factor of four in the range of log(L/L_\sun)~-3.2 through -4.2. This will provide unprecedented leverage in determining the true age of the oldest WDs by constraining the physics (\it e.g., phase separation, crystallization and convective efficiency) that dictate the cooling rates. In addition this will also provide an important constraint on the star formation history of the Galaxy from 1- 7 Gyr. The broadband filter data obtained in the DWFS provides the majority of our requirements-the high quality B_WRI photometry and background galaxy rejection to V=23. Here, we request time with the narrow band DDO-51 filter to separate cool WDs from other stellar types of similar T_eff. DDO51 photometry of half of the northern field was obtained in April 2002. We propose to observe the rest of the field to complement the DWFS data and identify the population of cool WDs including the oldest, and faintest ones. These data, along with follow- up spectroscopy with HET and Gemini GMOS, will ultimately resolve the controversies of the shape of the WDLF which we will use to constrain the interior physics of cooling WDs and place WD cosmochronometry on a firmer foundation.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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