The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XXVI. The calibration of population II secondary distance indicators and the value of the hubble constant
L. Ferrarese et al., The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XXVI. The calibration of population II secondary distance indicators and the value of the hubble constant, ASTROPHYS J, 529(2), 2000, pp. 745-767
A Cepheid-based calibration is derived for four distance indicators that ut
ilize stars in old stellar populations: the tip of the red giant branch (TR
GB), the planetary nebula luminosity function (PNLF), the globular cluster
luminosity function (GCLF), and the surface brightness fluctuation method (
SBF). The calibration is largely based on the Cepheid distances to 18 spira
l galaxies within ct = 1500 km s(-1) obtained as part of the Hubble Space T
elescope (HST) Key Project on the Extragalactic Distance Scale, but relies
also on Cepheid distances from separate HST and ground-based efforts. The n
ewly derived calibration of the SBF method is applied to obtain distances t
o four Abell clusters in the velocity range 3800-5000 km s(-1). Combined wi
th cluster velocities corrected for a cosmological flow model, these distan
ces imply a value of the Hubble constant of H-0 = 69 +/- 4 (random) +/- 6 (
systematic) km s(-1) Mpc(-1). This result assumes that the Cepheid PL relat
ion is independent of the metallicity of the variable stars; adopting a met
allicity correction as in Kennicutt et al. would produce a 5% +/- 3% decrea
se in H-0. Finally, the newly derived calibration allows us to investigate
systematics in the Cepheid, PNLF, SBF, GCLF, and TRGB distance scales.