{
  "bibcode": "2021GCN.31063....1D",
  "body": "S. de Wet (UCT), P.M. Vreeswijk (Radboud), A.J. Levan (Radboud),\n\nP.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT\n\nconsortium and the Stargate collaboration:\n\n\nWe observed the field of the Swift/BAT-GUANO short GRB candidate\n\nGRB211106A (Tohuvavohu et al., GCN 31049) with the 0.6m wide-field\n\nMeerLICHT optical telescope located at Sutherland, South Africa,\n\ntaking 10x60s exposures in the q-band starting at 2021-11-06,\n\n18:37:17 UT, approximately 14 hours after the GRB trigger.\n\n\nWe co-added the images to reach a full-frame 5-sigma AB limiting\n\nmagnitude of q = 21.90. An archival reference image with limiting\n\nmagnitude of q = 20.54 was used to perform image subtraction\n\nthrough our transient detection pipeline. The MeerLICHT field-of-view\n\nfully covers the BAT-GUANO error box and includes all the X-ray\n\nsources found through Swift-XRT follow-up observations\n\n(D'Elia et al., GCN 31051).\n\n\nOur transient pipeline finds 1 candidate in the BAT-GUANO error\n\nbox, at the same position as the XRT source coincident with a known\n\nX-ray source. The coordinates of the transient coincide with a star\n\nwith brightness G = 17.49 in the Gaia EDR3 catalogue, spatially\n\nvery close to galaxy LEDA 432583. We believe the transient detection\n\nis due to the star showing variable behaviour rather than a transient\n\nin the galaxy, owing to an increase in brightness of the star from\n\nq = 17.73 mag in the reference image to q = 17.47 in the new image.\n\nWe detect no source in our images at the position of the known X-ray\n\nsource 1RXS J225507.9-531312.\n\n\nNo other promising transient candidates are found in the error boxes\n\nof the 9 XRT sources nor the BAT-GUANO error box, down to a transient\n\nlimiting magnitude of 20.34.\n\n\nThere is one other potential transient candidate in our FOV, but it\n\nis 15.6��� away from the centre of the BAT-GUANO error box, so unlikely\n\nto be associated with GRB 211106A. The coordinates are\n\nRA, Dec (J2000) = 22:54:17.88, -52:58:35.22. The Legacy Survey DR9\n\nimages show a spiral galaxy at this position, which could be showing\n\nvariable behaviour or may be due to a transient near the galaxies' core.\n\n\nMeerLICHT is built and run by a consortium consisting of Radboud\n\nUniversity, University of Cape Town, the South African Astronomical\n\nObservatory, the University of Oxford, the University of Manchester\n\nand the University of Amsterdam.",
  "circularId": 31063,
  "createdOn": 1636453860000,
  "email": "dwtsim002@myuct.ac.za",
  "subject": "MeerLICHT follow-up of GRB 211106A",
  "submitter": "Simon de Wet at UCT  <dwtsim002@myuct.ac.za>",
  "eventId": "GRB 211106A"
}