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GCN Circular 34951

GRB 231104A: NOT upper limit
2023-11-05T11:47:50Z (7 months ago)
Zipei Zhu at NAOC <>
Z. Zhu, D. Xu (NAOC), D.B. Malesani (Radboud Univ. and DAWN/NBI), A. de Ugarte Postigo (OCA-CNRS), Z. Gray (NOT) report on behalf of a larger collaboration: 

We observed the field of GRB 231104A detected by Swift (Page et al., GCN 34938) and Fermi (Fermi GBM team, GCN 34937) using the the 2.56 m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observations started at 01:57:16 UT on 2023-11-05, i.e., ~ 1.0 day after the Swift/BAT trigger, and 9x200 s Sloan i-filter images were obtained.

No optical source is detected within or at the border of the Swift/XRT enhanced error circle (Goad et al., GCN 34940) down to upper limits of i > 24.2 mag (3-sigma), calibrated with the nearby Pan-STARRS stars and not corrected for Galactic extinction.
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