A supernova distance to the anchor galaxy NGC 4258^⋆

¹ Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK
e-mail: jpolshaw01@qub.ac.uk
² Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
³ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
⁴ Max-Planck-Institut fur Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching bei München, Germany
⁵ The Oskar Klein Centre & Department of Astronomy, Stockholm University, AlbaNova, 106 91 Stockholm, Sweden

Received: 6 July 2015
Accepted: 3 August 2015

Abstract

The fortuitous occurrence of a type II-Plateau (IIP) supernova, SN 2014bc, in a galaxy for which distance estimates from a number of primary distance indicators are available provides a means with which to cross-calibrate the standardised candle method (SCM) for type IIP SNe. By applying calibrations from the literature we find distance estimates in line with the most precise measurement to NGC 4258 based on the Keplerian motion of masers (7.6 ± 0.23 Mpc), albeit with significant scatter. We provide an alternative local SCM calibration by only considering type IIP SNe that have occurred in galaxies for which a Cepheid distance estimate is available. We find a considerable reduction in scatter (σ_I = 0.16 mag), but note that the current sample size is limited. Applying this calibration, we estimate a distance to NGC 4258 of 7.08 ± 0.86 Mpc.