A Test of the Calibration of the Tully-Fisher Relation Using Cepheid and SNIa Distances

TL;DR

This study tests the accuracy of Tully-Fisher distance estimates by comparing them with Cepheid and SNIa distances, revealing that Tully-Fisher distances are systematically underestimated and should be revised upwards.

Contribution

It provides the first direct calibration of Tully-Fisher distances using Cepheid and SNIa data, quantifying the necessary correction and its impact on the Hubble constant.

Findings

Tully-Fisher distances are too short by about 0.46 mag.

Previous Tully-Fisher distances should be increased by approximately 24%.

Revised Hubble constant is about 68 km/s/Mpc.

Abstract

We make a direct test of Tully-Fisher distance estimates to eleven spiral galaxies with HST Cepheid distances and to twelve spiral galaxies with SNIa distances. The HST Cepheid distances come from the work of Freedman (1997), Sandage et al (1996) and Tanvir et al (1995). The SNIa distances come from Pierce (1994), calibrated using the Cepheid results of Sandage et al (1996). The Tully-Fisher distances mostly come from the work of Pierce (1994). The results show that the Tully-Fisher distance moduli are too short with respect to the Cepheid distances by 0.46+-0.14mag and too short with respect to the SNIa distances by 0.46+-0.19mag. Combining the HST Cepheid and SNIa data suggests that, overall, previous Tully-Fisher distances were too short by 0.46+-0.11mag, a result which is significant at the 4sigma level. These data therefore indicate that previous Tully-Fisher distances should be revised upwards by 24+-6% implying, for example, a Virgo distance of 19.3+-1.9Mpc. The value of Ho from Tully-Fisher estimates is correspondingly revised downwards from Ho=84+-10 to Ho=68+-8.