TITLE: GCN CIRCULAR NUMBER: 31063 SUBJECT: MeerLICHT follow-up of GRB 211106A DATE: 21/11/09 10:31:00 GMT FROM: Simon de Wet at UCT <dwtsim002@myuct.ac.za> S. de Wet (UCT), P.M. Vreeswijk (Radboud), A.J. Levan (Radboud), P.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT consortium and the Stargate collaboration: We observed the field of the Swift/BAT-GUANO short GRB candidate GRB211106A (Tohuvavohu et al., GCN 31049) with the 0.6m wide-field MeerLICHT optical telescope located at Sutherland, South Africa, taking 10x60s exposures in the q-band starting at 2021-11-06, 18:37:17 UT, approximately 14 hours after the GRB trigger. We co-added the images to reach a full-frame 5-sigma AB limiting magnitude of q = 21.90. An archival reference image with limiting magnitude of q = 20.54 was used to perform image subtraction through our transient detection pipeline. The MeerLICHT field-of-view fully covers the BAT-GUANO error box and includes all the X-ray sources found through Swift-XRT follow-up observations (D'Elia et al., GCN 31051). Our transient pipeline finds 1 candidate in the BAT-GUANO error box, at the same position as the XRT source coincident with a known X-ray source. The coordinates of the transient coincide with a star with brightness G = 17.49 in the Gaia EDR3 catalogue, spatially very close to galaxy LEDA 432583. We believe the transient detection is due to the star showing variable behaviour rather than a transient in the galaxy, owing to an increase in brightness of the star from q = 17.73 mag in the reference image to q = 17.47 in the new image. We detect no source in our images at the position of the known X-ray source 1RXS J225507.9-531312. No other promising transient candidates are found in the error boxes of the 9 XRT sources nor the BAT-GUANO error box, down to a transient limiting magnitude of 20.34. There is one other potential transient candidate in our FOV, but it is 15.6’ away from the centre of the BAT-GUANO error box, so unlikely to be associated with GRB 211106A. The coordinates are RA, Dec (J2000) = 22:54:17.88, -52:58:35.22. The Legacy Survey DR9 images show a spiral galaxy at this position, which could be showing variable behaviour or may be due to a transient near the galaxies' core. MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam.