GCN Circular 34759

P. D'Avanzo (INAF-OAB), A. Reguitti (INAF-OAB / INAF-OAPd), L. Tomasella (INAF-OAPd), E. Cappellaro (INAF-OAPd), F. Onori (INAF-OAAb), 
F. De Luise (INAF-OAAb), L. Tartaglia (INAF-OAAb), R. Brivio (INAF-OAB), M. Ferro (INAF-OAB), V. D’Elia (ASI/SSDC), E. Brocato (INAF-OAAb) 
report on behalf ot the GRAWITA collaboration:


We carried out follow-up observations of the LIGO/Virgo/KAGRA GW trigger S230917af with the Schmidt telescopes sited in the INAF Asiago 
and Campo Imperatore observatories (Italy). 

Observations from Asiago have been carried out starting on 2023-09-19 at 00:44:52 UT (~ 1.61 days after the GW trigger) with the Clear, g and r filters. 
A second epoch has been carried out starting on 2023-09-19 at 21:14:12 UT (~ 2.47 days after the GW trigger) with the r filter. These observations 
covered ~ 86% of the localisation region of the low significance X-ray burst detected by MAXI (Negoro et al., GCN Circ. 34723
Not found
 
 
) and the position of sources 
S230917af_X3, S230917af_X4 and S230917af_X6 detected by Swift/XRT (Evans et al., GCN Circ. 34736
Not found
 
 
). 
Preliminary analysis, which includes image subtraction between the two epochs obtained in the r band, does not show evidence for promising candidate counterparts. 
The typical 3sigma limiting AB magnitudes are r ~ 21 mag and r ~ 22 mag for the first and second epoch, respectively. 


Observations from Campo Imperatore have have been carried out starting on 2023-09-19 at 20:14:33 UT (~ 2.42 days after the GW trigger) with the g and r filters.  
These observations covered ~ 86% of the localisation region of the low significance X-ray burst detected by MAXI and the position of sources S230917af_X3, 
S230917af_X4 and S230917af_X6 detected by Swift/XRT.
Preliminary analysis, which includes image subtraction with the images obtained in the first Asiago epoch, does not show evidence for promising candidate counterparts. 
The typical 3sigma limiting AB magnitudes are g ~ 21.4 mag and r ~ 20.8 mag.