GCN Circular 34415

Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy
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 observed the field of GRB 230812B (Lesage et al. GCN 34387
Not found
 
 
, Roberts et al. GCN 34391
Not found
 
 
, Scotton et al. GCN 34392
Not found
 
 
, Beardmore et al. GCN 34400
Not found
 
 
, Xiong et al. GCN 34401
Not found
 
 
, Casentini et al. GCN 34402
Not found
 
 
, Frederiks et al. GCN 34403
Not found
 
 
)
with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy.
Member of: 
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
AstroCampania Associazione

The observations started at 19:40 UT of 2023/08/13, after about 24 hours after the GRB trigger, at the end of twilight with clear skies, with principal telescope  SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 22 image of 240 sec each. All images are unfiltered, calibrated with masterdark and masterflat, stacked with Tycho Tracker and Astrometrica software
We have detected a clearly visible source at the enhanced position reported by Swift-XRT (Beardmore et al. GCN 34400
Not found
 
 
) and by optical telescopes (Zheng & Filippenko, GCN 34395
Not found
 
 
, Lipunov et al., GCN 34396
Not found
 
 
, Salgundi et al., GCN 34397
Not found
 
 
, Ackley et al., GCN 34398
Not found
 
 
, Kuin et al. GCN 34399
Not found
 
 
, Mao et al., GCN 34404
Not found
 
 
, Odeh et al., GCN 34405
Not found
 
 
, Moskvitin et al., GCN 34406
Not found
 
 
, Leonini et al., GCN 34408
Not found
 
 
, de Ugarte Postigo et al. GCN 34409
Not found
 
 
 & 34410, Belkin et al., GCN 34412
Not found
 
 
, Ruocco et al. GCN 34413
Not found
 
 
)
at following position

RA      (J2000.0)  16h 36m 31.47s 
Decl.   (J2000.0) +47° 51' 32.2"      

Preliminary photometry summing three sets of 7 images of 240 sec each, using Astrometrica and the UCAC4 catalog is as follows

2023 08 13.83014 16 36 31.46 +47 51 32.7          19.8 R      
2023 08 13.85209 16 36 31.52 +47 51 32.1          19.8 R      
2023 08 13.87403 16 36 31.47 +47 51 32.3          20.2 R      



Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.



The message may be cited.