TITLE:   GCN CIRCULAR
NUMBER:  25967
SUBJECT: LIGO/Virgo S190930t: Magellan/IMACS imaging of Swift J224718-581442 (AT2019sbk)
DATE:    19/10/07 08:01:49 GMT
FROM:    Subo Dong at KIAA-PKU  <dongsubo@pku.edu.cn>

Ping Chen (KIAA, Peking University),  Joshua D. Simon (Carnegie Observatories), and Subo Dong (KIAA, Peking University) report:

We observed the transient Swift J224718-581442 (AT2019sbk) (Tohuvavohu et al., GCN Circ. 25964), which was discovered in the UVOT and XRT search for the electromagnetic counterpart of LIGO/Virgo S190930t (LIGO/Virgo Collaboration GCN Circ. 25876). 

On 2019-Oct-07.14 UTC (JD = 2458763.64), we obtained g’-band (90s exposure) and i’-band (60s exposure) images with IMACS mounted on the 6.5 meter Magellan telescope at Las Campanas Observatory. We do not detect the source at the reported position (RA = 22:47:18.1 Dec = -58:14:50.80) in these images with approximate 3-sigma upper limits of ~22.4 mag in g’-band and ~22.9 mag in i’-band, respectively.