Cepheid distance estimation for Virgo cluster

A measurement of distance to the Virgo cluster and a few of its member gala xies by direct method is clearly important for a reliable determination of the Hubble constant as well as for studying the dynamics of a nearby rich g alaxy cluster. Cepheid variables in a few galaxies in the Virgo cluster wer e observed with the Hubble Space Telescope (HST) over the last few years. T his work is a reanalysis of the HST data following our study of the Galacti c and Magellanic Cloud Cepheids. The log (period) vs V-magnitude relation i s re-calibrated using the Galactic, LMC as well as the HST observations. Th e number density of Cepheid variables as a function of their period is used to determine the role of flux-limited incompleteness and a prescription is given to correct for this bias in the sample. The extinction correction is carried out using period vs mean [V-I](0) colour and V-amplitude vs (V-I) colour at the brightest phase relations. The distance and error estimation is based on L-1 minimization. The mean distance to Virgo cluster is estimat ed to be 20.5 +/- 1.8 (random)+/- 2.5 (systematic) Mpc.