OSU Navigation Bar

The Ohio State University University Libraries Knowledge Bank

The Knowledge Bank is scheduled for regular maintenance on Sunday, April 20th, 8:00 am to 12:00 pm EDT. During this time users will not be able to register, login, or submit content.

Spheroid Luminosity and Mass Functions from Hubble Space Telescope Star Counts

Please use this identifier to cite or link to this item: http://hdl.handle.net/1811/47934

Show full item record

Files Size Format View
fac_GouldA_TheA ... alJournal_1998_503_798.pdf 368.1Kb PDF View/Open

Title: Spheroid Luminosity and Mass Functions from Hubble Space Telescope Star Counts
Creators: Gould, Andrew; Flynn, Chris; Bahcall, John N.
Keywords: stars: luminosity function, mass function
subdwarfs
surveys
Issue Date: 1998-08-20
Publisher: American Astronomical Society
Citation: Andrew Gould, Chris Flynn, and John N. Bahcall, "Spheroid Luminosity and Mass Functions from Hubble Space Telescope Star Counts," The Astrophysical Journal 503, no. 2 (1998), doi:10.1086/306023
DOI: 10.1086/306023
Abstract: We analyze 166 spheroid subdwarfs (6.5 < M_V < 14.5) found in 53 fields observed with the Wide Field Planetary Camera on the Hubble Space Telescope. The fields cover 221 arcmin^2 over a wide range of directions. The spheroid luminosity function (LF) is inconsistent at about the 3 σ level with the local spheroid LF of Dahn et al. even when the normalization of the latter is corrected to take account of the latest data on spheroid kinematics. The difference may reflect systematic errors in one of the two studies or features of the spheroid spatial distribution that are not included in the simplest models. The mass function, which shows no obvious structure, can be represented by a power law, dN/d ln M α M^α, with α = 0.25 ± 0.32 over the mass range 0.71 Msun > M > 0.09 Msun. The spheroid therefore does not contribute significantly to microlensing unless the mass function changes slope dramatically in the substellar range. The total local mass density of spheroid stars (including remnants and unseen binary companions) is ρ ~ 6.4 × 10^-5 Msun pc^-3, with an uncertainty of about 50%. The power-law indices α = 0.25 for the spheroid and α = 0.44 for the disk (both uncorrected for binaries) are similar to those of globular clusters of moderate-to-high metallicity.
ISSN: 1538-4357
URI: http://hdl.handle.net/1811/47934
Bookmark and Share