THE MID-INFRARED TULLY-FISHER RELATION: CALIBRATION OF THE TYPE Ia SUPERNOVA SCALE AND H 0

This Letter builds on a calibration of the Type Ia supernova (SNIa) absolute distance scale begun with a core of distances based on the correlation between galaxy rotation rates and optical IC -band photometry. This new work extends the calibration through the use of mid-infrared photometry acquired at 3.6 μm with the Spitzer Space Telescope. The great virtue of the satellite observations is the constancy of the photometry at a level better than 1% across the sky. The new calibration is based on 39 individual galaxies and 8 clusters that have been the sites of well-observed SNIa. The new 3.6 μm calibration is not yet as extensively based as the IC -band calibration but is already sufficient to justify a preliminary report. Distances based on the mid-infrared photometry are 2% greater in the mean than reported at the IC band. This difference is only marginally significant. The IC -band result is confirmed with only a small adjustment. Incorporating a 1% decrease in the Large Magellanic Cloud distance, the present study indicates H 0 = 75.2 ± 3.0 km s–1 Mpc–1.