1998AJ....115.2359K -
Astron. J., 115, 2359-2368 (1998/June-0)
A V and I CCD mosaic survey of the Ursa Minor dwarf spheroidal galaxy.
KLEYNA J.T., GELLER M.J., KENYON S.J., KURTZ M.J. and THORSTENSEN J.R.
Abstract (from CDS):
We discuss a Johnson-Cousins V- and I-band CCD mosaic survey of the Ursa Minor dwarf spheroidal galaxy (dSph) to V ∼ 22. We covered UMi with 27 10'.5 x 10'.5 overlapping CCD frames, each frame consisting of two 300 s exposures in each of V and I. We also observed several regions ∼3° from UMi to obtain an estimate of contamination by galaxies and Galactic stars. We report the first H-R diagram of an entire dSph. Separation of dwarf stars from foreground stars by color allows a robust estimation of the structural parameters of UMi. We examine earlier evidence of two lumps in the UMi stellar distribution. We detect a statistically significant asymmetry in the stellar distribution of UMi along the major axis. Structure in the stellar distribution of UMi might indicate a tidal origin for UMi's high observed mass-to-light ratio. We demonstrate a technique for obtaining the absolute magnitude of UMi from horizontal-branch star counts compared with M92; this method of luminosity estimation is independent of the distance to UMi. We obtain MV=-8.87±σ(MV), where σ(MV)=0.14 if M92 is a perfect calibrator and σ(MV)≲0.35 is an upper bound on the error arising from differences in stellar populations. Our value for MV is consistent with earlier measurements and has a smaller uncertainty.
Abstract Copyright:
∼
Journal keyword(s):
Galaxies: Dwarf - Galaxies: Individual: Name: Ursa Minor - Galaxies: Stellar Content - Galaxies: Local Group
Simbad objects:
3
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:1998AJ....115.2359K and select 'bookmark this link' or equivalent in the popup menu