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GCN Circular 35160

GRB 231117A: Continued GTC Observations
2023-11-22T20:56:27Z (7 months ago)
Simone Dichiara at Pennsylvania State University <>
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Simone Dichiara (PSU), Alan M. Watson (UNAM), Nathaniel R. Butler (ASU), Eleonora Troja (Università di Roma Tor Vergata), Brendan O’Connor (CMU), Rosa L. Becerra (UNAM), Nissim Fraija (UNAM), William Lee (UNAM), Kin López (UNAM), and Margarita Pereyra (UNAM) report:

We observed the field of GRB 231117A (Laha et al., GCN 35071; Navaneeth et al., GCN 35072; Beardmore et al., GCN3574; Cattaneo et al., GCN 35075; Svinkin et al., GCN 35079; Cheung et al., GCN 35081; Dafcikova et al., GCN 53095; Busman et al. GCN 35138; O'Connor et al., GCN 35139; Watson et al., GCN 35153, Kuin et al., GCN 35154) with the OSIRIS instrument on the GTC telescope from 2023-11-21 20:34 to 21:16 UTC (113.5 to 114.2 hours after the trigger).  We obtained total integrations of 480 s in r and 960 s in z with a seeing of about 0.9 arcsec.

We detect the source in both bands but, even with our good seeing, reliable photometry will require image subtraction. We measure r = 21.8 +/- 0.1 AB, with an uncertain contribution from the host galaxy. This value is not corrected for Galactic extinction.

Further observations are planned.

We thank the staff of the GTC, especially David García Álvarez and Antonio Cabrera, for their help with these observations.
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