{
  "bibcode": "2016GCN.19492....1C",
  "body": "S. B. Cenko (NASA/GSFC), W.-F. Fong (Arizona), A. J. Levan (Warwick), A. Cucchiara (STScI), E. Berger (Harvard), and D. A Perley (DARK) report on behalf of a larger collaboration:\n\nWe imaged the location of GRB160601A (Kocevski et al., GCN 19478) with the Gemini Multi-Object Spectrograph (GMOS) mounted on the 8m Gemini North telescope.  We obtained a series of 5 x 180 s r-band images beginning at 6:02 UT on 2016 June 2 (~ 15.3 hr after the BAT trigger).  The candidate optical afterglow proposed by Malesani et al (GCN 19485; their Source 1) is confirmed to be fading (see also Schulze et al., GCN 19488, Tello et al., GCN 19491).  Using nearby point sources from SDSS for calibration, we measure a magnitude of r = 23.69 +/- 0.05 at this time.  \n\nWe note that the source appears to be (marginally) extended in our GMOS images, and therefore host contamination may to be present in the above magnitude estimate.",
  "circularId": 19492,
  "createdOn": 1464880014000,
  "email": "brad.cenko@nasa.gov",
  "subject": "GRB160601A: Gemini Imaging",
  "submitter": "S. Bradley Cenko at NASA/GSFC  <brad.cenko@nasa.gov>",
  "eventId": "GRB 160601A"
}