Extended Data Fig. 1: Optical spectra of AT2022tsd obtained with Keck/LRIS.
From: Minutes-duration optical flares with supernova luminosities
Spectra are binned using 3-Å bins. Regions with identified narrow host-galaxy emission lines, used to measure the best-fit redshift of z = 0.2564 ± 0.0003, are marked. Regions used to search for z = 0 emission lines, as would be expected from a foreground Galactic transient, are also marked.
