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The white dwarf luminosity function - A possible probe of the galactic haloThe dynamically inferred dark halo mass density, amounting to above 0.01 solar masses/cu pc at the sun's Galactocentric radius, can be composed of faint white dwarfs provided that the halo formed in a sufficiently early burst of star formation. The model is constrained by the observed disk white dwarf luminosity function which falls off below log (L/solar L) = -4.4, due to the onset of star formation in the disk. By using a narrow range for the initial mass function and an exponentially decaying halo star formation rate with an e-folding time equal to the free-fall time, all the halo dark matter is allowed to be in cool white dwarfs which lie beyond the falloff in the disk luminosity function. Although it is unlikely that all the dark matter is in these dim white dwarfs, a definite signature in the low-luminosity end of the white dwarf luminosity function is predicted even if they comprise only 1 percent of the dark matter. Current CCD surveys should answer the question of the existence of this population within the next few years.
Document ID
19900054785
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Tamanaha, Christopher M.
(California Univ. Berkeley, CA, United States)
Silk, Joseph
(California, University Berkeley, United States)
Wood, M. A.
(California Univ. Berkeley, CA, United States)
Winget, D. E.
(Texas, University; McDonald Observatory, Austin, United States)
Date Acquired
August 14, 2013
Publication Date
July 20, 1990
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 358
ISSN: 0004-637X
Subject Category
Astrophysics
Funding Number(s)
CONTRACT_GRANT: NSF AST-86-00507
CONTRACT_GRANT: NGT-50210
CONTRACT_GRANT: NSF AST-85-52457
Distribution Limits
Public
Copyright
Other
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