TITLE: GCN CIRCULAR NUMBER: 20753 SUBJECT: LIGO/Virgo G275404: NOT Follow-up of MASTER OT DATE: 17/02/26 15:44:25 GMT FROM: Mansi M. Kasliwal at Caltech C. Fremling (OKC), F. Taddia (OKC), R. Amanullah (OKC), J. Sollerman (OKC), M. M. Kasliwal (Caltech) report on behalf of the iPTF and GROWTH collaborations We observed the transient MASTER OT J173532.70+103810.5 reported in LVC GCN #20740, using ALFOSC on the Nordic Optical Telescope, on 2017-02-26 at 05:40 UT. We do not detect any transient at the reported coordinates, in agreement with observations from the Liverpool Telescope (LVC GCN # 20750). The 3-sigma limiting (unfiltered) magnitude of our stacked acquisition frames at the expected position of the transient is ~21.1 mag. This would imply an extremely fast rate of fading > approx. 10 mag / day! We caution that there is a variable star (PTF1717w) which is within a few arcsec of the reported MASTER OT position. But this nearby variable star only shows variations between roughly 19.0-19.6 mag in R-band in archival PTF data. Additional follow-up is encouraged.