JWST identifies SN Ares, a lensed Type IIb supernova at redshift 1.276
JWST spectra show SN Ares is a Type IIb supernova at redshift 1.276, with two more images due in about 70 years.
Astronomers have identified SN Ares, a strongly lensed supernova at a spectroscopic redshift of 1.276, in a paper posted to arXiv on 23 October. The supernova sits in a massive, triply imaged host galaxy behind the MACS J0308.9+2645 galaxy cluster. The paper lists Conor Larison and 71 other authors.
JWST/NIRSpec spectra span the rest-frame optical to near-infrared. They show helium features at 5876, 7065 and 10830 angstroms, along with Hα and Paβ. Comparison with local core-collapse supernova spectra and light curves leads to a Type IIb classification. The authors say it is the highest-redshift member of its class identified spectroscopically.
The spectrum is estimated to come from 34 rest-frame days after the radioactive peak, with an uncertainty of plus 10 and minus 9 days.
A lens model built with recent JWST data indicates Ares is the first image to arrive. It will reappear in two future images near the centre of the cluster plane in roughly 70 years or more, with predicted magnifications of about 5 times and 1.5 times.
Sourcearxiv.org