{
  "bibcode": "2021GCN.30206....1P",
  "body": "D. A. Perley (LJMU), Y. Yao (Caltech), A. Y. Q. Ho (UC Berkeley), M. \nBulla (Stockholm/OKC), I. Andreoni (Caltech), M. Coughlin (U. \nMinnesota), and E. Kool (Stockholm/OKC) report:\n\nThe Zwicky Transient Facility (ZTF; ATel #11266) observed the location \nof GRB 210610B (Page et al., GCN 30170) during the night of 2021-06-11 \nUT as part of the regular operations of the ZTF high-cadence partnership \nsurvey.  Four separate observations of the field (ZTF field ID 533) were \nobtained between 2021-06-11 05:34:44 and 2021-06-11 08:38:29, two each \nin g-band and r-band.\n\nThe associated optical transient (e.g., Page et al., GCN 30170; Kumar et \nal., GCN 30174) was automatically identified by the ZTF image \nsubtraction pipeline and assigned the identifier ZTF21abfmpwn.  The \nsource was independently flagged as a fast transient candidate by both \nthe ZTF fast-transient filter pipeline developed by A. Ho and Y. Yao \n(Perley et al. 2021, arXiv:2103.01968) and by the ZTFReST pipeline \n(Andreoni et al. 2021, arXiv:2104.06352), on the basis of its rapid \nevolution over the course of the night and coincidence with a galaxy in \nPan-STARRS and Legacy Survey reference imaging.\n\nWe provide the following photometry:\n\nMJD           t_GRB(d)     filter   magnitude\n59376.2324    0.4050       g        18.49 +/- 0.10\n59376.2751    0.4477       r        18.29 +/- 0.07\n59376.3206    0.4932       r        18.44 +/- 0.07\n59376.3600    0.5326       g        18.81 +/- 0.07\n\nPhotometry is as provided by the ZTF alert packets and is \nreference-subtracted.  Magnitudes are AB and are not corrected for \nGalactic extinction.\n\nZTF is supported by the National Science Foundation under Grant No. \nAST-2034437 and a collaboration including Caltech, IPAC, the Weizmann \nInstitute for Science, the Oskar Klein Center at Stockholm University, \nthe University of Maryland, Deutsches Elektronen-Synchrotron and \nHumboldt University, the TANGO Consortium of Taiwan, the University of \nWisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore \nNational Laboratories, and IN2P3, France. Operations are conducted by \nCOO, IPAC, and UW.\n\nDisclaimerNone",
  "circularId": 30206,
  "createdOn": 1623435072000,
  "email": "d.a.perley@ljmu.ac.uk",
  "subject": "GRB 210610B: Zwicky Transient Facility afterglow detection",
  "submitter": "Daniel Perley at Liverpool JMU  <d.a.perley@ljmu.ac.uk>",
  "eventId": "GRB 210610B"
}