Type II-P supernovae as standardized candles: improvements using near-infrared data

Abstract

We present the first near-infrared Hubble diagram for Type II-P supernovae (SNe), to further explore their value as distance indicators.We use a modified version of the standardized candle method, which relies on the tight correlation between the absolute magnitudes of Type II-P SNe and their expansion velocities during the plateau phase. Although our sample contains only 12 II-P SNe and they are necessarily local (z <0.02), we demonstrate using near-infrared JHK photometry that it may be possible to reduce the scatter in the Hubble diagram to 0.1– 0.15 mag. While this is potentially similar to the dispersion seen for Type Ia SNe, we caution that this needs to be confirmed with a larger sample of II-P SNe in the Hubble flow.