Direct Determination of Hubble Parameter Using Type IIn Supernovae

TL;DR

The paper presents a new Dense Shell Method for measuring cosmic distances using Type IIn Supernovae, providing a direct, ladder-independent way to estimate the Hubble constant with promising results.

Contribution

It introduces the Dense Shell Method, a novel approach that directly measures distances with Type IIn Supernovae, bypassing the cosmic distance ladder.

Findings

Median distance to SN 2006gy: 68^{+19}_{-15} Mpc

Estimated Hubble parameter: 79^{+23}_{-17} km/s/Mpc

Method yields satisfactory results for luminous Type IIn Supernovae

Abstract

We introduce a novel approach, a Dense Shell Method (DSM), for measuring distances for cosmology. It is based on original Baade idea to relate absolute difference of photospheric radii with photospheric velocity. We demonstrate that this idea works: the new method does not rely on the Cosmic Distance Ladder and gives satisfactory results for the most luminous Type IIn Supernovae. This allows one to make them good primary distance indicators for cosmology. Fixing correction factors for illustration, we obtain with this method the median distance of 68^{+19}_{-15} (68%CL) Mpc to SN 2006gy and median Hubble parameter 79^{+23}_{-17} (68%CL) km/s/Mpc.