TITLE: GCN CIRCULAR NUMBER: 41090 SUBJECT: GRB 250713A: OHP/T193 upper limit DATE: 25/07/14 09:21:22 GMT FROM: Stephane Basa at UAR Pytheas/OHP, LAM stephane.basa@lam.fr
O. Braun (LAM/OHP/Pytheas/AMU), C. Adami (LAM/Pytheas/AMU), B. Schneider (LAM), S. Basa (LAM/OHP/Pytheas/AMU), E. Le Floc'h (CEA/Irfu), report on behalf of a larger collaboration:
We observed the field of the GRB 250713A (Maggi et al., GCN 41078; Fu et al., GCN 41079) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained 14 exposures (for a total of 60 min) in the r-band starting at 22:26:02 UT on 2025-07-13 (5.3 hours after the trigger).
In the stacked images, we do not detect any new source at the MXT position (Maggi et al., GCN 41078). The preliminary upper limit is r > 22.3 mag (AB) at 3 sigma.
No other credible source compatible with a GRB is detected in MISTRAL's field of view up to r > 21.7 mag (AB) at 5 sigma.
The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the magnitudes are not corrected for Galactic extinction. We used the STDWeb/STDPipe tools (Karpov 2025).
We acknowledge the excellent support from the Observatoire de Haute-Provence and in particular Jean Balcaen for the MISTRAL observations.
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