TITLE: GCN CIRCULAR NUMBER: 21882 SUBJECT: LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993 DATE: 17/09/14 05:25:42 GMT FROM: Eleonora Troja at GSFC/Swift M. Wieringa (CSIRO), R. Ricci (INAF), L. Piro (INAF) and E. Troja (UMD/GSFC) report: On 08 Sep 2017, we observed the field of SSS17a (Coulter et al., LVC GCN 21529) with the Australia Telescope Compact Array (ATCA) at the central frequencies of 16.7 and 21.2 GHz, each with a bandwidth of 2 GHz. At the position of GW counterpart (Adams et al., LVC GCN 21816) we report the following 3-sigma upper limit: 17/21 GHz < 35 uJy Further observations are planned. We thank the CSIRO staff for approving and executing these observations.