Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/43959

Title

Globular cluster luminosity functions and the Hubble constant from WFPC2 imaging: the dominant group elliptical NGC 5846

Author(s)

Forbes, Duncan A.

Abstract

The Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) has several advantages over ground-based observations for the study of globular cluster luminosity functions (GCLFs) and distance determination. Here we present WFPC2 data on the globular clusters associated with NGC 5846. This giant elliptical is the dominant galaxy in a small, compact group located ∼13 Mpc beyond the Virgo cluster. We have detected over 1200 globular clusters in three (central, north, and south) separate pointings. The luminosity functions in each of these pointings are statistically the same, indicating that the mean luminosity (mass) does not vary between ∼3 and 30 kpc from the galaxy center. This suggests that dynamical friction and bulge shocking destruction processes are insignificant. We have fit a Gaussian and t5 profile to the GCLF (of the combined pointings) and find that it is well represented by a turnover magnitude of m0V=25.05±0.10 and a dispersion of σ=1.34±0.06. Our 50% incompleteness level is ∼1 mag fainter than the turnover. After applying a metallicity correction to the "universal" GCLF turnover magnitude, we derive a distance modulus of (m-M)=32.32±0.23. For a group velocity VCMB = 1883±28 km s-1, the Hubble constant is H0=65±8 km s-1 Mpc-1.

Publication type

Journal article

Source

Astronomical Journal, Vol. 112, no. 6 (Dec 1996), pp. 2448-2453

Publication year

1996

Keyword(s)

Distance scale;  Elliptical galaxies;  Globular clusters;  HST;  Hubble Space Telescope;  NGC 5846;  WFPC2;  Wide Field and Planetary Camera 2

Publisher

University of Chicago Press

ISSN

0004-6256

Publisher URL

http://dx.doi.org/10.1086/118194

Copyright

Copyright © 1996 The American Astronomical Society. All rights reserved.

Peer reviewed