Difference: GCNCIRCULAR21898 ( vs. 1)

A. Pozanenko (IKI), A. Volnova (IKI), E. Mazaeva (IKI), P. Minaev (IKI), A. Moskvitin (SAO RAS), M. Krugov (AFIF) report on behalf of IKI-GW follow-up collaboration:

We report a photometry of the counterpart SSS17a/DLT17ck (Coulter et al. GCN 21529; Yang et al., GCN 21531) of LIGO/Virgo trigger G298048 (LIGO Scientific Collaboration and Virgo Collaboration, GCNs 21509, 21513) with RC-1000 1m telescope of CHILESCOPE observatory (GCNs 21618, 21635, 21644). The observations carried out in a clear filter in four epochs. We used last epoch (7.49278 days after trigger) to construct a mask for subsequent mask subtraction. The PSF photometry is based on several nearby USNO-B1.0 stars (R2 magnitudes).

Photometry of the transient SSS17a/DLT17ck is following

Date UT start t-T0 Filter Exp. OT Err.
(mid, days) (s)

2017-08-19 23:30:33 2.46157 CR 10*180 19.12 0.06
2017-08-20 23:21:09 3.47840 CR 13*180 20.04 0.08
2017-08-21 23:32:09 4.49409 CR 22*180 20.14 0.12
2017-08-24 23:53:39 7.49278 CR 20*180 >21.0 (3 sigma upper limit)

-- ThomasKupfer - 20 Sep 2017