{
  "subject": "EP250427A/GRB250427A: Keck/LRIS redshift",
  "submittedHow": "email",
  "eventId": "GRB 250427A",
  "submitter": "Ryan Chornock at UC Berkeley <chornock@berkeley.edu>",
  "circularId": 40265,
  "bibcode": "2025GCN.40265....1C",
  "body": "\nR.Chornock, E. Hammerstein, X. Guo (UC Berkeley) report:\n\nWe observed the optical afterglow (GCNs 40258, 40259, 40260, 40261, 40263, 40264) of EP250427a (GCN 40257)/GRB 250427a (GCN 40262) using the Low-Resolution Imaging Spectrometer on the Keck-I telescope at a mean time of 12:36UT on 2025 Apr 27. Observations covered the range 3140-10300 Angstroms. \n\nA continuum is well detected across the full spectral range with many absorption lines present. We identify a strong doublet at observed wavelengths of 3900.3,3906.7 Angs as CIV at z=1.519 from the highest redshift system detected. There are also many lines (C II, C IV, Fe II, Mg I, Mg II) from a stronger low-redshift system at z=1.406.\n\nFurther analysis is ongoing.\n\n",
  "createdOn": 1745763082913
}