C. McCully, D. A. Howell, G. Hosseinzadeh, D. Hiramatsu, I. Arcavi, S.
Vasylyev (UCSB/Las Cumbres Obs), S. Valenti (UC Davis)
L. P. Singer (NASA/GSFC), C. Fremling (Caltech), and M. M. Kasliwal
(Caltech) on behalf of the GROWTH (Global Relay of Observatories
Watching Transients Happen) collaboration report:
We observed the optical transient, SSS17a/DLT17ck (Coulter et al., LVC GCN
21529) on 2017-08-19 08:36:22, +1.83 days after the LIGO/Virgo trigger
G298048 (LVC GCN Circ. 21509, 21513), for one hour with the robotic FLOYDS
instrument mounted on the Las Cumbres Observatory Faulkes Telescope South
at the Siding Spring Observatory in Australia. We detect the continuum of
the transient at low signal-to-noise level.
We also observed SSS17a/DLT17ck on 2017-08-20 01:01:54, +2.51 days after
the LIGO/Virgo trigger, with the Gemini Multi-Object Spectrograph (GMOS) on
the Gemini-South 8-m telescope. We observed in our red setting for 763
seconds and 128 seconds in our blue setting until the telescope reached its
altitude limit. We again detect the continuum at low signal to noise level
due to the high airmass at which the observations were made and the limited
exposure times due to observing constraints.
We thank the LCO staff, specifically Mark Bowman and Mark Willis, and the
Gemini staff, specifically Karleyne Silva and Laura Ferrarese, for their
assistance with these observations.