GCN Circular 37131
Subject
GRB 240809A: Bassano Bresciano Observatory optical observations
Date
2024-08-10T12:21:02Z (5 months ago)
From
Ulisse Quadri at Bassano Bresciano Observatory <osservatoriobassano@gmail.com>
Via
Web form
U.Quadri, L.Strabla and P.Madurini (Bassano Bresciano Astronomical Observatory),
Members of:
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/SSV-GRB section.
GAC - Gruppo Astrofili Cremonesi.
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),
B. De Simone (Universita' degli Studi Di Salerno),
report:
We imaged the field of GRB 240809A detected by SWIFT(trigger 1247745) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy.
The observations started 11.38 hours after the GRB trigger, At the end of twilight with our Newton telescope D=450 mm F/D=4.5.
We co-added 150 exposures of 20 sec each (total 50 min).
Start T0+ End T0+ CR lim
11.38 hour 12.29 hour 20.6
We detected a (fading) afterglow in the error box of the XRTcandidate (Evans et al., GCN 37110; Wang et al., GCN 37113; Dubay et al., GCN 37114; Jiang et al., GCN 37116; V. Lipunov et al., GCN 37117; Gottumukkala et al., GCN 37122; Shilling & Evans, GCN 37123; Mohan et al., GCN 37125; Zheng & Filippenko, GCN 37127; B. Schneider et al., GCN 37129) at the following position (+/- 3 arcsec):
RA (J2000.0) = 15 50 10.46
DEC(J2000.0) = -02 19 04.6
The results of our photometry are:
---------------------------------------------
Date UT Exp Afterglow
Middle (Min) CR-mag
---------------------------------------------
2024 08 09.84773 50 19.7 +/- 0.2
---------------------------------------------
CR magnitude is unfiltered with R zero point.
Comparison stars used:
------------------------------
Pan-STARRS obj ID R-Mag
------------------------------
105212375756448208 16.639
105202375684658035 17.916
105202375288851708 17.912
105192375172794156 17.312
105182375066235940 17.998
------------------------------
Magnitudes were estimated with the pan-STARRS cat and are derived using Lupton (2005) equations and are not corrected for galactic dust extinction.
Reference:
http://www.osservatoriobassano.org/grb.asp
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