1998/12/17 by Chris Flynn, Flynn, Chris, Andrew Gould +4
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9812321
12 pages, 6 figures, LaTeX, paspconf.sty, to be published in The Third Stromlo Symposium: The Galactic Halo, eds. B.K. Gibson, T.S. Axelrod, and M.E. Putnam. Astron. Soc. Pac. Conf. Series, Vol. 666, 1999
arxiv created 1998/12/17 · openalex publication_date 1998/12/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We describe a program of star counts in the range 19 < I < 26 made with the WFPC cameras aboard the Hubble Space Telescope. Red (V-I > 1.0) stars at these magnitudes are primarily disk and spheroid M dwarfs. The stars are found both on dedicated images as part of the parallel program and by using appropriate archive data. We measure the faint end of the luminosity functions of the disk and spheroid (i.e. stellar halo). We measure the low mass end of the mass function and show that M dwarfs do not dominate the total disk or spheroid mass. We place strong I-band constraints on the amount of halo dark matter in the form of low mass stars (such as M dwarfs or cool white dwarfs). The disk and spheroid contribute only a minor amount of optical depth toward the Magellanic clouds.