{
  "bibcode": "2020GCN.28161....1S",
  "body": "K. W. Smith, S. Srivastav, O. McBrien, S. J. Smartt, J. Gillanders,\nP. Clark, M. Fulton, D. O'Neill, D. R. Young, M. McCollum (QUB),\nA. Townsend (University of Manchester, QUB), T.-W. Chen (Stockholm),\nJ. Anderson (ESO), L. Denneau, A. Heinze, J. Tonry, H. Weiland (IfA,\nUniversity of Hawaii), B. Stalder (LSST), A. Rest (STScI), D. E. Wright\n(University of Minnesota)\n\nThe transient AT2020qer reported by Gompertz et al (GCN 28159) as a\npossible counterpart to GRB 200723A (Fermi GBM; GCN 28155), was detected\nindependently by ATLAS, the twin telescope system on Haleakala and Mauna\nLoa as part of normal sky operations (Tonry et al. 2018, PASP, 130f4505,\nSmith et al. 2020, PASP, 132f1014) on 2020-07-24.32 (MJD 59054.32).\n\nForced photometry at that position shows clear, rising activity before\nthe GRB event.\n\nATLAS forced photometry:\nMJD          dt   m      dm    filter\n59048.36523 -5.33 19.50  0.15  c\n59048.36843 -5.32 20.13  0.24  c\n59048.37442 -5.32 19.36  0.14  c\n59048.40300 -5.29 19.47  0.15  c\n59050.33364 -3.36 18.89  0.09  o\n59050.33733 -3.35 19.10  0.11  o\n59050.34287 -3.35 18.95  0.10  o\n59050.35486 -3.34 19.01  0.10  o\n59054.31747  0.63 18.18  0.06  o\n59054.32069  0.63 18.20  0.05  o\n59054.32670  0.64 18.34  0.06  o\n59054.33871  0.65 18.27  0.06  o\n\nwhere dt is the time difference between ATLAS MJD and the GRB trigger.\n\nWe therefore conclude that AT2020qer is unrelated to GRB 200723A and is\nprobably a young supernova candidate.",
  "circularId": 28161,
  "createdOn": 1595614919000,
  "email": "k.w.smith@qub.ac.uk",
  "subject": "GRB 200723A: ATLAS observations of GOTO candidate AT2020qer",
  "submitter": "Ken Smith at Queen's University Belfast  <k.w.smith@qub.ac.uk>",
  "eventId": "GRB 200723A"
}