{
  "submitter": "Laura Cotter at Cornell <laura.cotter@ucdconnect.ie>",
  "subject": "GRB 261029A: NOT imaging and spectroscopic redshift z = 3.27",
  "eventType": [
    "GRB"
  ],
  "eventId": "GRB 261029A",
  "editedOn": 1793282778106,
  "body": "L. Cotter (Cornell), L. B. He (NAOC), D. O’Neill (Birmingham), D. Xu (NAOC), N. R. Tanvir (Leicester), D. B. Malesani (DAWN/NBI and Radboud), J. An (NAOC) and K. Jhass (Birmingham) report on behalf of a larger collaboration:\n\nWe observed the optical and near-infrared counterpart (O’Neill et al., GCN 46073; He et al., GCN 46078; Wang et al., GCN 46079; De et al., GCN 46080) of the Fermi and SVOM GRB 261029A (Fermi GBM team, GCN 46071; Goto et al., GCN 46072) using the Nordic Telescope (NOT) equipped with the ALFOSC imager. Observations began on 2026-10-29 at 02:52:39 UT, approximately 86 min post-trigger. We obtained 3x300 s exposures in the SDSS-r band and 5x200 s exposures in the SDSS-z band. The optical counterpart candidate is well detected in our images; photometry yields the following preliminary magnitudes:\n\nr: 16.61 +/- 0.01 AB at a mid time of 93.5 min post trigger;\nz: 16.62 +/- 0.01 AB at a mid time of 114 min post trigger.\n\nPhotometry was calibrated against Pan-STARRS DR2 catalog stars and is not corrected for Galactic extinction.\n\nSpectroscopic observations began at 03:53:31 UT consisting of 4x1200 s exposures using grism 4, which covers the wavelength range between 3200 and 9600 Å. Based on a preliminary reduction of the spectra using IRAF, we observe a number of absorption features matching well Lyman delta, gamma, beta, alpha, Si II, O I, C II, Si IV, C IV, Al II, all at a common redshift of z = 3.27, which we consider to be the redshift of GRB 261029A.\n",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Laura Cotter at Cornell <laura.cotter@ucdconnect.ie>",
  "format": "text/plain",
  "createdOn": 1793252482552,
  "circularId": 46081,
  "version": 2,
  "submittedHow": "web"
}