Evolving dark energy or supernovae systematics?

ABSTRACT Recent results from the Dark Energy Spectroscopic Instrument (DESI) collaboration have been interpreted as evidence for evolving dark energy. However, this interpretation is strongly dependent on which Type Ia supernova (SN) sample is combined with DESI measurements of baryon acoustic oscillations and observations of the cosmic microwave background radiation. The strength of the evidence for evolving dark energy ranges from ${\sim} 3.9 \sigma$ for the Dark Energy 5 year (DES5Y) SN sample to ${\sim} 2.5 \sigma$ for the Pantheon+ sample. The cosmology inferred from Pantheon+ sample alone is consistent with the Planck lambda cold dark matter ($\Lambda$CDM) model and shows no preference for evolving dark…