HOMOGENEOUS VELOCITY-DISTANCE DATA FOR PECULIAR VELOCITY ANALYSIS .2.CALIBRATION OF FIELD SAMPLES

This is the second in a series of papers in which we assemble and anal yze a homogeneous catalog of peculiar velocity data In Paper I, we tre ated two Tully-Fisher (TF) cluster samples. Here, we study four TF fie ld samples: the I-band sample of Mathewson, Ford, & Buchhorn, the r-ba nd samples of Willick and Courteau-Faber, and the H-band sample of Aar onson et al. as revised by Tormen & Burstein. In Paper III, we will co mbine these spiral samples with elliptical data to form the Mark III C atalog of Galaxy Peculiar Velocities, which will be used as input for POTENT and other velocity analyses. We derive the TF slope and scatter separately for each sample, correcting for selection biases and self- consistency determining internal-extinction coefficients. We find no e vidence for a luminosity dependence of internal extinction. We fit bot h forward and inverse TF relations and, by comparing the two, validate the bias corrections applied to the forward fits. By matching TF dist ances for several hundred galaxies common to two or more samples, we d etermine the relative zero points of the various TF relations, The glo bal zero point is set by the Han-Mould TF calibration carried out in P aper I. We calibrate the TF relations after grouping field galaxies in redshift space, making conservative use of preliminary TF relations b ased on Hubble flow distances. The differences between the preliminary and final TF scatter estimates indicate typical radial peculiar veloc ities of similar to 250-300 km s(-1). We find observed scatters sigma( TF) approximate to 0.38-0.43 mag for the r- and I-band samples, larger than many recent estimates, and estimate the intrinsic TF scatter to be similar to 0.30 mag. Based on simulated catalogs, we find that our observed scatter estimates are good to less than or similar to 5%.