SN 2016jhj at redshift 0.34: extending the Type II supernova Hubble diagram using the standard candle method

TL;DR

This paper extends the use of Type II supernovae as standard candles to higher redshifts, constructing the most distant SN II Hubble diagram to date, demonstrating their potential for cosmology beyond low redshift.

Contribution

It presents the first high-redshift SN II Hubble diagram using the standard candle method with new deep survey data, surpassing previous redshift limitations.

Findings

Constructed the highest-redshift SN II Hubble diagram to date

Achieved an observed dispersion of 0.27 mag in the distance measurements

Demonstrated the viability of SN II cosmology with upcoming large surveys

Abstract

Although Type Ia supernova cosmology has now reached a mature state, it is important to develop as many independent methods as possible to understand the true nature of dark energy. Recent studies have shown that Type II supernovae (SNe II) offer such a path and could be used as alternative distance indicators. However, the majority of these studies were unable to extend the Hubble diagram above redshift $z=0.3$ because of observational limitations. Here, we show that we are now ready to move beyond low redshifts and attempt high-redshift ($z \gtrsim 0.3$) SN~II cosmology as a result of new-generation deep surveys such as the Subaru/Hyper Suprime-Cam (HSC) survey. Applying the "standard candle method" to SN$\sim$2016jhj ($z=0.3398 \pm 0.0002$; discovered by HSC) together with a low-redshift sample, we are able to construct the highest-redshift SN II Hubble diagram to date with an observed dispersion of 0.27 mag (i.e., 12-13% in distance). This work demonstrates the bright future of SN~II cosmology in the coming era of large, wide-field surveys like that of the Large Synoptic Survey Telescope.