{
  "bibcode": "2017GCN.21632....1I",
  "body": "M. Im, C. Choi, J. Kim, Lim, G. H. M. Lee (SNU), S.-L. Kim, C.-U. Lee\n(KASI) on behalf of the KU collaboration\n\n\nWe continued to monitor the strong optical counterpart candidate of\nLIGO/Virgo G298048 (GCNs 210505, 21509, 21513), SSS17a/DLT17ck(Coutler et\nal. GCN 21529; Allam et al. GCN 21530; Yang et al. GCN 21531; Arcavi et al.\nGCN 21538; also see notes below for a list of optical/NIR observation\nreports). The observation was carried out using three KMTNet 1.6m\ntelescopes and other small telescopes (Im et al. GCNs 21563, 21566, 21597)\nat three sites , the Siding Spring Observatory (SSO), the South African\nAstronomical Observatory (SAAO), and the Cerro-Tololo Inter-American\nObservatory (CTIO). We imaged the object with B,V,R,I,i,z, filters and\nmedium-band images at 825, 875, 925, 975 nm.\n\nWe confirm that the object is fading in optical and its continuum shape has\nbeen becoming redder as time goes on (e.g., Cenko et al. GCN 21572; Lyman\net al. GCN 21582; Wiseman et al. GCN 21584; Chambers et al. GCN 21590;\nMalesani et al. GCN 21590; Chen et al. GCN 21608). A part of the data from\nseveral sites are presented below.\n\nUT V R I Site\n\n08-18.72 17.8(0.1) 17.4(0.1) 17.3(0.1) SAAO\n\n08-18.99 18.3(0.1) 17.6(0.1) 17.4(0.1) CTIO\n\n08-19.72 19.4(0.1) 18.3(0.1) 17.9(0.1) SAAO\n\n08-19.98 19.8(0.1) 18.4(0.1) 18.2(0.1) CTIO\n\nThe observations and further analysis of the data are ongoing.\n\nNotes: It is remarkable that more than 40 optical/NIR follow-up\nimaging/spectroscopic observations of the optical counterpart candidates\nhave been reported in three days since the first discovery report of the\noptical counterpart. For reference, we list them here (let me know if I am\nmissing any). They are, Coutler et al. (GCN 21529, 21567), Allam et al.\n(GCN 21530), Yang et al. (GCNs 21531, 21579), Melandri et al. (GCN 21532,\n21596), Arcavi et al. (GCNs 21538, 21565, 21581), Nicholl et al. (GCN\n21541, 21580, 21585), Tanvir et al. (GCN 21544), Lipunov et al. (GCNs\n21546, 21570, 21587), Drout et al. (GCN 21547), Evans et al. (GCN 21550),\nSimon et al. (GCN 21551), Singer et al. (GCN 21552), Chambers et al. (GCN\n21553, 21590, 21617), Wolf et al. (GCN 21560), Yoshida et al. (GCN 21561,\n21586), Im et al. (GCNs 21563, 21566, 21597), Cenko et al. (GCN 21572),\nLyman et al. (GCN 21582), Kilpatrick et al. (GCN 21583), Wiseman et al.\n(GCN 21584), Malesani et al. (GCN 21591), D���Elia et al. (GCN 21592),\nWiersema et al. (GCN 21594), Tominaga et al. (GCN 21595), Valenti et al.\n(GCN 21606), Chen et al. (GCN 21608), Pozanenko et al. (GCN 21618), Nakaoka\net al. (GCN 21623), Castro-Tirado et al. (GCN 21624), Coward et al. (GCN\n21627).",
  "circularId": 21632,
  "createdOn": 1503330581000,
  "email": "myungshin.im@gmail.com",
  "subject": "LIGO/Virgo G298048: Continued monitoring of the optical counterpart candidate",
  "submitter": "Myungshin Im at Seoul National U  <myungshin.im@gmail.com>",
  "eventId": "LIGO/Virgo G298048"
}