Difference: GCNCIRCULAR21595 ( vs. 1)

Tominaga, N. (Konan Univ.), Yoshida, M., Tanaka, M., Terai, T., Nakata, F., Furusawa, H., Koshida, S. (NAOJ), Utsumi, Y., Kawabata K. S. (Hiroshima Univ.), Motohara, K., Ohsawa, R., Morokuma, T., Yasuda, N. (Univ. of Tokyo), Kawai, N. (Tokyo Tech), and Asakura, Y. (Nagoya Univ.) on behalf of the J-GEM collaboration

We performed z-band imaging observations for the gravitational wave event G298048 (GCN 21505; 21509; 21513) with Hyper Suprime-Cam attached to the Subaru telescope on August 19 2017 UT (Yoshida et al. GCN 21586).

We made photometric calibration with Pan-STARRS1 catalog (Chambers et al. 2016) using HSC pipeline (Bosch et al. 2017) and obtained psf magnitude of SSS17a (Coulter et al. 2017; GCN 21529) as

z = 17.8 (AB) (2017-08-19 05:26--05:52UT),

which is 0.5 mag fainter than the psf magnitude obtained with Subaru/HSC on August 18 UT (Yoshida et al. GCN 21561). The fading nature of SSS17a in the z-band is consistent with the reports in Nicholl et al. (GCN 21580) and Chambers et al. (GCN 21590).

-- ShaonGhosh - 19 Aug 2017