{
  "bibcode": "2018GCN.23515....1A",
  "body": "Authors: Tomas Ahumada (UMD), Michael W. Coughlin (Caltech), S. Bradley\nCenko (NASA GSFC), Leo P. Singer (NASA GSFC), Shaon Ghosh (UWM), Igor\nAndreoni (Caltech), Mansi M. Kasliwal (Caltech), Eric C. Bellm (UW), V.\nZach Golkhou (UW), Ryosuke Itoh (Tokyo Tech), Anna Ho (Caltech), Yuhan Yao\n(Caltech), Jacob Jencson (Caltech), Matt Hankins (Caltech), Kishalay De\n(Caltech), Virginia Cunningham (UMD) on behalf of the ZTF and GROWTH\ncollaborations and the KPED team\n\nWe observed the localization region of the short GRB181126B (trigger\n564897175) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi\nsatellite with the Palomar 48-inch telescope equipped with the 47 square\ndegree Zwicky Transient Facility (ZTF) camera. We obtained two sets of 180\nsecond r-band images covering 1400 square degrees beginning at 5:15 UT on\n2018 November 26 (1 hour and 23 minutes after the burst trigger time).\nAccounting for area lost to processing failures, this corresponds to\nanalyzing 66% of the probability enclosed. Beginning at 6:06 UT on 2018\nNovember 27 we observed the updated IPN localization with ZTF using 300\nsecond r-band exposures. The observations covered 709 square degrees. Once\nagain accounting for processing failures, 77% of the enclosed probability\nwas analyzed.\n\nThe images were processed through the ZTF reduction and image subtraction\npipelines at IPAC to search for potential counterparts. 394\nhigh-significance transient and variable candidates were identified by our\npipeline in the area observed,  most (383) of which had previous detections\nwith ZTF in the days and weeks prior to the GRB trigger time (e.g.,\nsupernovae, active galactic nuclei, CV).\n\nFurther follow-up of 11 transients was obtained with the Kitt Peak EMCCD\nDemonstrator (KPED) on the Kitt Peak 84-inch telescope on November 28.\nAdditionally, we obtained follow-up spectroscopy of 6 candidates with the\nLow Resolution Imaging Spectrometer (LRIS) on Keck I, the nights of\nDecember 1 and December 3. The candidates are listed below, however no\nphotometric evolution or spectral classification was consistent with an\noptical counterpart.\n\n----------------------------------------------------------------------------------------------------------------------------\n\n       ZTF ID         RA DEC      last non-detection discovery    KPED\nClassification\n\n----------------------------------------------------------------------------------------------------------------------------\n\n\n                             deg deg date in 2018          Nov 26 Nov 28\n\n----------------------------------------------------------------------------------------------------------------------------\nZTF18achtkfy     103.5113 37.0748    11-09 g<19.94 r = 19.69   r = 20.95\nSN* (Rising)\nZTF18acpftxl     102.7187 29.3472     11-21 r<20.43 r = 20.11   r > 20.93\nAsteroid* (1 det)\nZTF18achflqs      70.2895 23.8902   11-10 r<20.37 r = 20.74   r = 20.26 SN*\n(Rising)\nZTF18acrkcxa     73.7605 22.6787   11-21 r<19.68 r = 21.21    r = 20.87 SN*\n(Rising)\nZTF18acrkkpc     95.8148 10.323    11-21 r<20.17 r = 20.17    r = 19.85 SN*\n(Rising)\nZTF18aadwfrc     94.3249 50.4844   11-25 r<19.33 r = 18.96    r = 18.13 SN\nII z=0.04\nZTF18acrfond     59.8623 24.589     11-25 r<19.38 r = 19.93    r = 18.87 SN\nIa z=0.117\nZTF18acrfymv     94.5049 44.1813   11-25 r<19.13 r = 20.05    r = 19.60 S\nNIc-BL\n<http://skipper.caltech.edu:8080/cgi-bin/growth/edit_comment.cgi?name=ZTF18acrfymv&id=11173>\nz=0.\n<http://skipper.caltech.edu:8080/cgi-bin/growth/edit_comment.cgi?name=ZTF18acrfymv&id=11174>\n072\nZTF18acptgzz     68.3852 -1.6475    11-25 r<19.22 r = 19.01   r = 19.04 SN\nIa z=0.096\n\nZTF18acbyrll       88.8695 29.4723 11-21   r<19.84 r = 18.79 r > 21.87\n  Asteroid* (1 det)\n\nZTF18acrewzd    70.3221 -1.7688     11-25 r<19.17 r = 20.21   r = 19.9 SN\nIa z=0.13\n\n-------------------------------------------------------------------------------------------------------------------------\n\n*Classification from photometric data points.\n\nThe median 5-sigma upper limit for an isolated point source in ZTF images\nwas r > 20.5 mag for the observations made on November 26 and r > 21.1 mag\nfor the observations made on November 27.\n\nZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266\n<http://www.astronomerstelegram.org/?read=11266>), and includes IPAC; WIS,\nIsrael; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; MOST, Taiwan; UW\nMilwaukee, USA and LANL USA. ZTF acknowledges the generous support of the\nNSF under AST MSIP Grant No 1440341. Alert distribution service provided by\nDIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system,\nsupported by NSF PIRE grant 1545949.",
  "circularId": 23515,
  "createdOn": 1544159690000,
  "email": "tahumada@astro.umd.edu",
  "subject": "GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175)",
  "submitter": "Tomas Ahumada at U. of Maryland  <tahumada@astro.umd.edu>",
  "eventId": "GRB 181126B"
}