The Pantheon+ Analysis: The Full Dataset and Light-Curve Release

TL;DR

This paper presents an extensive dataset of 1701 light curves from 1550 spectroscopically confirmed Type Ia supernovae, enhancing the statistical power for cosmological parameter inference and including low-redshift SNe for improved Hubble constant and dark energy measurements.

Contribution

It provides a significantly expanded and detailed supernova dataset across multiple surveys, including low-redshift SNe, enabling more precise cosmological analyses and systematic studies.

Findings

Increased sample size from previous Pantheon analysis.

Inclusion of low-redshift SNe for H0 and w measurements.

Comparison of properties among SNe observed by multiple surveys.

Abstract

Here we present 1701 light curves of 1550 spectroscopically confirmed Type Ia supernovae (SNe Ia) that will be used to infer cosmological parameters as part of the Pantheon+ SN analysis and the SH0ES (Supernovae and H0 for the Equation of State of dark energy) distance-ladder analysis. This effort is one part of a series of works that perform an extensive review of redshifts, peculiar velocities, photometric calibration, and intrinsic-scatter models of SNe Ia. The total number of light curves, which are compiled across 18 different surveys, is a significant increase from the first Pantheon analysis (1048 SNe), particularly at low redshift ($z$). Furthermore, unlike in the Pantheon analysis, we include light curves for SNe with $z<0.01$ such that SN systematic covariance can be included in a joint measurement of the Hubble constant (H$_0$) and the dark energy equation-of-state parameter ($w$). We use the large sample to compare properties of 151 SNe Ia observed by multiple surveys and 12 pairs/triplets of "SN siblings" - SNe found in the same host galaxy. Distance measurements, application of bias corrections, and inference of cosmological parameters are discussed in the companion paper by Brout et al. (2022b), and the determination of H$_0$ is discussed by Riess et al. (2022). These analyses will measure w with $\sim3\%$ precision and H$_0$ with 1 km/s/Mpc precision.