The Discovery of the Most Distant Known Type Ia Supernova at Redshift 1.914

Understand

We present the discovery of a Type Ia supernova (SN) at redshift $z = 1.914$ from the CANDELS multi-cycle treasury program on the \textit{Hubble Space Telescope (HST)}.

• This SN was discovered in the infrared using the Wide-Field Camera 3, and it is the highest-redshift Type Ia SN yet observed.
• We classify this object as a SN\,Ia by comparing its light curve and spectrum with those of a large sample of Type Ia and core-collapse supernovae (SNe).
• Its apparent magnitude is consistent with that expected from the $\Lambda$CDM concordance cosmology.