TITLE:   GCN CIRCULAR
NUMBER:  33935
SUBJECT: GRB 230506B: Chandra localization of the X-ray afterglow
DATE:    23/06/07 19:35:15 GMT
FROM:    Brendan O'Connor at UMD <oconnorb@umd.edu>

B. O'Connor (GWU), S. Dichiara (PSU), E. Troja (UTV), S. B. Cenko (NASA-GSFC, UMD), C. Kouveliotou (GWU), T. Sakamoto (AGU), A. Kutyrev (UMD), G. Ryan (Perimeter), R. Ricci (INAF), G. Bruni (INAF):

We carried out two Chandra ToO observation of GRB 230506B beginning on May 11, 2023 at 06:59:55 UT and June 01, 2023 at 19:31:19 UT with ACIS-S as part of program 24400201 (PI: O'Connor) for a total of 19 ks and 55 ks, respectively. The initial observation began ~4.8 days after the GRB trigger (Dichiara et al. GCN 33727). 

Within the XRT localization (Burrows et al. GCN 33737), we detect a single point source at RA, DEC = 21:47:55.6, 44:30:41.6 with an uncertainty of 0.9" (90% confidence, statistical + systematic). The source displays rapid fading between the two Chandra epochs confirming that it is the X-ray afterglow of GRB 230506B.

We would like to thank Patrick Slane, Harvey Tananbaum, Dan Schwartz, Scott Wolk, 
and the CXO staff for rapidly approving and planning this observation.