Difference: GCNCIRCULAR21682 ( vs. 1)

E. Troja (UMD/GSFC), A. Watson (UNAM), S. Covino (INAF), W. H. Lee (UNAM), N. Butler (ASU), J. Becerra-Gonzalez (UMD/GSFC), A. Lien (UMBC), T. Sakamoto (AGU), and P. D'Avanzo (INAF)

and

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 field of the transient SSS17a in NGC 4993 (Coulter et al. 2017; GCN 21529) with the Flamingos-2 (F2) instrument and the Gemini Multi-Object Spectrograph (GMOS) mounted on the Gemini- South 8-m telescope starting on 2017 Aug 20.98 UT, ~3.5 days after LIGO/Virgo trigger G298048 (LVC GCN Circ. 21509, 21513). Imaging observations were carried out in the g, r, i, z, J, H and K filters. The source is detected in all bands with a preliminary magnitude J~17.2. We also obtained a pair of 1200s GMOS spectra with the R400 and the B600 gratings. We do not detect any significant emission or absorption lines over the red featureless continuum.

We thank the Gemini staff, particularly Hwihyun Kim, Ricardo Salinas, and Laura Ferrarese for their support of these operations.

-- ThomasKupfer - 24 Aug 2017