{
  "bibcode": "2017GCN.21245....1F",
  "body": "W. Fong, P. Milne, N. Smith and D. Zaritsky (University of Arizona) report\non behalf of the AZTEC (Arizona Transient Exploration and Characterization)\nteam:\n\n\"We observed the field of the Fermi/LAT candidate (Omodei et al., GCN\n21227) with the Wide Field Camera (WFCAM) mounted on the 3.8-m United\nKingdom Infrared Telescope (UKIRT) on Mauna Kea beginning on 2017 Jun 9.238\nUT (1.15 days post-trigger; LSC/Virgo et al. GCN 21221). We obtained a\ntotal of 360-sec of J-band imaging in 1.4\" seeing at a mean airmass of 1.8.\nThe observations cover the entire Fermi/LAT localization region (90%\nconfidence; Omodei et al., GCN 21227), as well as the positions of all\nSwift/XRT sources reported in Evans et al. (GCN 21233).\n\nTo assess variability, we obtained a second set of observations beginning\non 2017 Jun 10.240 UT (2.16 days post-trigger and 24.0 hr after the initial\nUKIRT observations). These observations cover only 75% of the Fermi/LAT\nlocalization area, as well as the positions of XRT Sources 2-7.\n\nWe perform photometry of all known near-IR sources in or around the\npositions of the XRT sources, and find no evidence for variability relative\nto archival 2MASS values. Digital image subtraction of the two UKIRT epochs\nusing the ISIS software package reveals no residuals, indicating no\nvariability from 1.15 to 2.16 days post-trigger for 75% of the LAT\nlocalization region, to a 3-sigma limit of J>18.9 AB mag. We note that this\npreliminary analysis is based on reductions produced by the quick-look\npipeline ORAC-DR, and a final reduction of the images are expected to be at\nleast ~1.5 mag deeper.\n\nWe thank Sam Benigni and Watson Varricatt for their assistance in planning\nand executing these observations.\"",
  "circularId": 21245,
  "createdOn": 1497145620000,
  "email": "wenfai@gmail.com",
  "subject": "LIGO/Virgo G288732: UKIRT near-IR imaging of the Fermi/LAT candidate",
  "submitter": "Wen-fai Fong at U of Arizona  <wenfai@gmail.com>",
  "eventId": "LIGO/Virgo G288732"
}