The Astrophysical Journal Letters (Jan 2024)

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

  • J. D. R. Pierel,
  • M. Engesser,
  • D. A. Coulter,
  • C. DeCoursey,
  • M. R. Siebert,
  • A. Rest,
  • E. Egami,
  • W. Chen,
  • O. D. Fox,
  • D. O. Jones,
  • B. A. Joshi,
  • T. J. Moriya,
  • Y. Zenati,
  • A. J. Bunker,
  • P. A. Cargile,
  • M. Curti,
  • D. J. Eisenstein,
  • S. Gezari,
  • S. Gomez,
  • M. Guolo,
  • B. D. Johnson,
  • M. Karmen,
  • R. Maiolino,
  • R. M. Quimby,
  • B. Robertson,
  • M. Shahbandeh,
  • L. G. Strolger,
  • F. Sun,
  • Q. Wang,
  • T. Wevers

DOI
https://doi.org/10.3847/2041-8213/ad6908
Journal volume & issue
Vol. 971, no. 2
p. L32

Abstract

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We present the James Webb Space Telescope (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 ± 0.007. The transient was identified in deep (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic follow-up 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 ( c ∼ 0.9) despite a host galaxy with low extinction and has a high Ca ii velocity (19,000 ± 2000 km s ^−1 ) 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 (≲1 σ ) with ΛCDM. 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.

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