We present a measurement of the Hubble Constant based on Cepheid distances to 27 galaxies within 20 Mpc .
We take the Cepheid data from published measurements by the Hubble Telescope Key Project on the Distance Scale ( H _ { 0 } KP ) .
We calibrate the Cepheid Period-Luminosity ( PL ) relation with data from over 700 Cepheids in the LMC obtained by the OGLE collaboration ; we assume an LMC distance modulus of 18.50 mag ( d _ { { LMC } } = 50.1 kpc ) .
Using this PL calibration we obtain new distances to the H _ { 0 } KP galaxies .
We correct the redshifts of these galaxies for peculiar velocities using two distinct velocity field models : the phenomenological model of Tonry et al .
and a model based on the IRAS density field and linear gravitational instability theory .
We combine the Cepheid distances with the corrected redshifts for the 27 galaxies to derive H _ { 0 } , the Hubble constant .
The results are H _ { 0 } = 85 \pm 5 { km } { s } ^ { -1 } { { Mpc } } ^ { -1 } ( random error ) at 95 % confidence when the IRAS model is used , and 92 \pm 5 { km } { s } ^ { -1 } { { Mpc } } ^ { -1 } when the phenomenological model is used .
The IRAS model is a better fit to the data and the Hubble constant it returns is more reliable .
Systematic error stems mainly from LMC distance uncertainty which is not directly addressed by this paper .
Our value of H _ { 0 } is significantly larger than that quoted by the H _ { 0 } KP , H _ { 0 } = 71 \pm 6 { km } { s } ^ { -1 } { { Mpc } } ^ { -1 } .
Cepheid recalibration explains \sim 30 \% of this difference , velocity field analysis accounts for \sim 70 \% .
We discuss in detail possible reasons for this discrepancy and future study needed to resolve it .