Blue Supergiants and the Zero-point of the Tully–Fisher Relation: A Path to a New Independent Test of the Hubble Constant

Blue supergiant distances of nearby galaxies obtained with the flux-weighted gravity–luminosity relationship are used for a measurement of the zero-points of Tully–Fisher relationships at different photometric passbands. The Cousins I band and the infrared WISE bands W1 and W2 are investigated. The results are compared with previous work using Cepheid and tip of the red giant branch distances. No significant differences were encountered. This supports the large values of the Hubble constant greater than 73 km s −1 Mpc −1 found with the Tully–Fisher distance ladder work over the last decade. Applying blue supergiant distances on the I -band Tully–Fisher relation observations yields a Hubble constant H 0 = 76.2 ± 6.2 km s −1 Mpc −1 . The large uncertainty is caused by the still relatively small blue supergiant galaxy sample size but will be reduced in future work.