Discovery of An Apparent Red, High-Velocity Type Ia Supernova at z = 2.9 with JWST

TL;DR

This paper reports the discovery and analysis of a high-redshift, red, high-velocity Type Ia supernova at z=2.9 using JWST, providing insights into its properties and implications for cosmology.

Contribution

First detection of a high-z, red, high-velocity Type Ia supernova with JWST, demonstrating its potential for studying distant supernovae and cosmological parameters.

Findings

SN 2023adsy is a high-redshift (z=2.9) Type Ia supernova with unique spectral features.

Despite its redness, SN 2023adsy's luminosity distance aligns with standard cosmological models.

SN 2023adsy is standardizable, supporting the use of SNe Ia for high-redshift cosmology.

Abstract

We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS$+53.13485$$-$$27.82088$ with a host spectroscopic redshift of $2.903\pm0.007$. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (E(B-V)$\sim0.9$) despite a host galaxy with low-extinction and has a high Ca II velocity ($19,000\pm2,000$km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-z Ca-rich population. Although such an object is too red for any low-z cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement ($\lesssim1\sigma$) with $\Lambda$CDM. Therefore unlike low-z Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-z truly diverge from their low-z counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.