Globular Cluster Luminosity Functions and the Hubble Constant From WFPC2 Imaging: The Giant Elliptical NGC 4365

Abstract

view Abstract Citations (25) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Globular Cluster Luminosity Functions and the Hubble Constant From WFPC2 Imaging: The Giant Elliptical NGC 4365 Forbes, Duncan A. Abstract The turnover, or peak, magnitude in a galaxy's globular cluster luminosity function (GCLF) may provide a standard candle for an independent distance estimator. Here we examine the GCLF of the giant elliptical NGC 4365 using photometry of ~350 globular clusters from the Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2). The WFPC2 data have several advantages over equivalent ground-based imaging. The membership of NGC 4365 in the Virgo cluster has been the subject of recent debate. We have fit a Gaussian and t_5_ profile to the luminosity function and find that it can be well represented by a turnover magnitude of m^0^_v_ = 24.2+/-03 and a dispersion σ = 1.28+/-0.15. After applying a small metallicity correction to the "universal" globular cluster turnover magnitude, we derive a distance modulus of (m - M) = 31.6+/-0.3 which is in reasonable agreement with that from surface brightness fluctuation measurements. This result places NGC 4365 about 5 Mpc beyond the Virgo cluster core. For a V_CMB_ = 1592+/-24 km s^-1^ the Hubble constant is H_0_ = 72^+10^_-12_ km s^-1^ Mpc^-1^. We also describe our method for estimating a local specific frequency for the GC system within the central 5 h^-1^ kpc which has fewer uncertain corrections than a total estimate. The resulting value of 6.4+/-1.5 indicates that NGC 4365 has a GC richness similar to other early-type galaxies. Publication: The Astronomical Journal Pub Date: September 1996 DOI: 10.1086/118069 arXiv: arXiv:astro-ph/9611140 Bibcode: 1996AJ....112..954F Keywords: GALAXIES: INDIVIDUAL: NGC 4365; GLOBULAR CLUSTERS: GENERAL; DISTANCE SCALE; Astrophysics E-Print: 12 pages, Latex, full paper also available at http://www.ucolick.org/~forbes/home.html full text sources arXiv | ADS | data products SIMBAD (7) NED (4) MAST (1) ESA (1)