TITLE:   GCN CIRCULAR
NUMBER:  37540
SUBJECT: GRB 240916A: NOT optical observation
DATE:    24/09/17 23:53:34 GMT
FROM:    sqjiang at NAOC <sqjiang@bao.ac.cn>

S.Q. Jiang (NAOC), D. B. Malesani (DAWN/NBI and Radboud Univ.), D. Xu (NAOC), B. N. Hauptmann (NOT) report on behalf of a large collaboration:

We observed the optical counterpart (AT 2024vlp / GOTO24fzn: Gompertz et al., GCN 37522; Jiang et al., GCN 37526; Pieterse et al., GCN 37532) of GRB 240916A, detected by Fermi/GBM (Fermi GBM Team, GCNs 37518, 37535) and INTEGRAL SPI/ACS (Pawar et al., GCN 37519) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera, and obtained 3 x 300 s frames in the Sloan r-band, starting at 20:03:23.239 UT on 2024-09-17, i.e., 42.675 hr after the Fermi/GBM trigger.

The afterglow is clearly detected in our stacked image, with a magnitude r = 20.58 +/- 0.04 (AB), calibrated against nearby Pan-STARRS stars and not corrected for Galactic extinction.