TITLE:   GCN CIRCULAR
NUMBER:  36960
SUBJECT: GRB 240727A Bassano Bresciano Observatory upper limit
DATE:    24/07/28 08:09:05 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Observatory <osservatoriobassano@gmail.com>

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 240727A detected by SWIFT(trigger 1245074)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy.

The observations started 19.78 hour after the GRB trigger, At the end of twilight 
with our Newton telescope D=450 mm F/D=4.5.

Weather conditions were good.

We co-added 2 series of 30 exposures of 60 sec each.

Start T0+      End T0+    Vlim
19.78 hour   20.86 hour    20

We did not found any optical counterpart in the error box of the XRTcandidate.
Parsotan et al.(GCN 36938), WeiKanget al.(GCN 36939), X. Liu et al.(GCN 36940).

Magnitudes were estimated with the pan-STAR cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.