Difference: GCNCIRCULAR21684 ( vs. 1)

R. Chornock (Ohio University) and E. Berger (Harvard) report on behalf of a larger collaboration:

Further to our previous report (LVC GCN 21638), we have continued near-infrared observations of the optical counterpart (Coulter et al., LVC GCN 21529; Allam et al., LVC GCN 21530; Yang et al., LVC GCN 21531) to the LIGO/Virgo source G298048 (GCNs 21509, 21513) using FLAMINGOS2 on Gemini-South (PI: Chornock).

Over the course of our initial observations, obtained during the first 4.5 days after the GW trigger, the H-band flux from the near-infrared source was not strongly variable. However, in H-band acquisition images obtained tonight (20170824 at 23:47 UT, t~7.5 d after the GW trigger), the NIR counterpart appears substantially fainter (by >1 magnitude) compared to our previous observations three nights earlier. A phase of more rapid NIR fading may have begun.

We thank the entire Gemini-South staff, but particularly H. Kim, G. Diaz, J. Chavez, P. Candia, and the director, Laura Ferrarese, for their support of these observations.

-- ThomasKupfer - 25 Aug 2017