GCN Circular 39774
Subject
GRB 250317B: Leavitt Observatory optical upper limit
Event
Date
2025-03-18T20:04:16Z (8 months ago)
From
leavittob@gmail.com
Via
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L. Moretti, E. Pavoni (Leavitt Observatory, Italy)
Members of:
GRB/UAI - Gamma Ray Burst Section of Unione Astrofili Italiani
ATA - Associazione Tuscolana di Astronomia
In a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan),
Y. Niino (Tokyo University, Institute of Astronomy),
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
report:
We observed the field of the GRB 250317B triggered by SVOM/ECLAIRs (Zhao et al., GCN 39752 and GCN 39753) and SVOM/MXT (Zhao et al., GCN 39752 and GCN 39753; and Götz et al., GCN 39756) with our RC telescope (D=250 mm, F/D=8) of Leavitt Observatory, Manciano, Italy.
The observations started approximately 19 hours after the SVOM/ECLAIRs trigger time, with good weather conditions, stacking a set of unfiltered FITS frames. Images were processed using the astropy package (Astropy Collaboration et al., 2022ApJ...935..167A).
In the stacked frame, we did not found any optical uncatalogued object within the SVOM error circle.
Mid-Time (UTC) Limit (clear filter) Error
2025-03-17T21:18:03 >20.0 +/- 0.1
Magnitudes were estimated with the BP-band of Gaia DR3 catalogue (*) and are not corrected for galactic dust extinction.
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Reference:
https://leavittobservatory.altervista.org
(*) https://gea.esac.esa.int/archive/documentation/GEDR3/Data_processing/chap_cu5pho/cu5pho_sec_photSystem/cu5pho_ssec_photRelations.html