The supernova Ia 2011fe in M101, its tip of the red-giant branch (TRGB) distance, and the value of H_0

TL;DR

This paper determines the Hubble constant using SN2011fe in M101, deriving its light curve parameters, applying TRGB distance, and analyzing a sample of SNe Ia to estimate H_0 as approximately 64 km/s/Mpc.

Contribution

It provides a new estimate of the Hubble constant based on SN2011fe and TRGB distances, highlighting the potential for improved precision with more TRGB-based measurements.

Findings

H_0 estimated at 64.3 km/s/Mpc with uncertainties

Derived SN magnitudes consistent with standard decline rate

TRGB distances improve H_0 measurement accuracy

Abstract

The light curve parameters of the normal type Ia SN2011fe are derived from the rich archive of the AAVSO. This leads, together with the TRGB distance modulus of (m-M) = 29.39 +/- 0.05 of the parent galaxy M101, to maximum magnitudes of the unreddened SN of M_B = -19.45 +/- 0.08, M_V = -19.46 +/- 0.08, and M_I = -19.25 +/- 0.06 (for the standard decline rate of Delta m_15 = 1.1). When these values are inserted into the Hubble line defined by 62 SNe Ia with 3000 < v < 20,000 km/s - and considering also four other SNe Ia with TRGB distances - one obtains a large-scale value of the Hubble constant of H_0 = 64.3 +/- 1.9 +/- 3.2. This value can be much improved in the future by using only TRGB distances of SNe Ia.