Distance Measurements to Parent Galaxies of SNIa by the Tip of the Red-Giant Branch

Abstract

Abstract—We use the archival data obtained with the Hubble space telescope to measure distances by the tip of the red-giant branch (TRGB) method to SNIa parent galaxies. Our sample consists of four galaxies: NGC2841, NGC4496A, NGC4535, and NGC4527. For three of them, we were able to determine only the lower bounds of the distance. For the galaxy NGC4527, we estimated the TRGB distance modulus: (m − M)0 = 30m.56 ± 0m.09. Combining our measurements with the published data, we compared the supernova distance moduli using the MLCS2k2 method and the host galaxies with the TRGB method. SNIa distance moduli show systematically higher value at 0m.15–0m.18 relative to the scale of the TRGB distances. This corresponds to overestimation of the luminosity of supernovae with the MLCS2k2 method. We estimated the luminosity of supernovae at the brightness maximum as MV = −19m.33 ± 0m.03 which allows one to accept the following Hubble constant: H0 = 70.4 ± 1.0 km s−1 Mpc−1.