//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23515 SUBJECT: GRB 181126B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 564897175) DATE: 18/12/07 05:14:50 GMT FROM: Tomas Ahumada at U. of Maryland Authors: Tomas Ahumada (UMD), Michael W. Coughlin (Caltech), S. Bradley Cenko (NASA GSFC), Leo P. Singer (NASA GSFC), Shaon Ghosh (UWM), Igor Andreoni (Caltech), Mansi M. Kasliwal (Caltech), Eric C. Bellm (UW), V. Zach Golkhou (UW), Ryosuke Itoh (Tokyo Tech), Anna Ho (Caltech), Yuhan Yao (Caltech), Jacob Jencson (Caltech), Matt Hankins (Caltech), Kishalay De (Caltech), Virginia Cunningham (UMD) on behalf of the ZTF and GROWTH collaborations and the KPED team We observed the localization region of the short GRB181126B (trigger 564897175) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi satellite with the Palomar 48-inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. We obtained two sets of 180 second r-band images covering 1400 square degrees beginning at 5:15 UT on 2018 November 26 (1 hour and 23 minutes after the burst trigger time). Accounting for area lost to processing failures, this corresponds to analyzing 66% of the probability enclosed. Beginning at 6:06 UT on 2018 November 27 we observed the updated IPN localization with ZTF using 300 second r-band exposures. The observations covered 709 square degrees. Once again accounting for processing failures, 77% of the enclosed probability was analyzed. The images were processed through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts. 394 high-significance transient and variable candidates were identified by our pipeline in the area observed, most (383) of which had previous detections with ZTF in the days and weeks prior to the GRB trigger time (e.g., supernovae, active galactic nuclei, CV). Further follow-up of 11 transients was obtained with the Kitt Peak EMCCD Demonstrator (KPED) on the Kitt Peak 84-inch telescope on November 28. Additionally, we obtained follow-up spectroscopy of 6 candidates with the Low Resolution Imaging Spectrometer (LRIS) on Keck I, the nights of December 1 and December 3. The candidates are listed below, however no photometric evolution or spectral classification was consistent with an optical counterpart. ---------------------------------------------------------------------------------------------------------------------------- ZTF ID RA DEC last non-detection discovery KPED Classification ---------------------------------------------------------------------------------------------------------------------------- deg deg date in 2018 Nov 26 Nov 28 ---------------------------------------------------------------------------------------------------------------------------- ZTF18achtkfy 103.5113 37.0748 11-09 g<19.94 r = 19.69 r = 20.95 SN* (Rising) ZTF18acpftxl 102.7187 29.3472 11-21 r<20.43 r = 20.11 r > 20.93 Asteroid* (1 det) ZTF18achflqs 70.2895 23.8902 11-10 r<20.37 r = 20.74 r = 20.26 SN* (Rising) ZTF18acrkcxa 73.7605 22.6787 11-21 r<19.68 r = 21.21 r = 20.87 SN* (Rising) ZTF18acrkkpc 95.8148 10.323 11-21 r<20.17 r = 20.17 r = 19.85 SN* (Rising) ZTF18aadwfrc 94.3249 50.4844 11-25 r<19.33 r = 18.96 r = 18.13 SN II z=0.04 ZTF18acrfond 59.8623 24.589 11-25 r<19.38 r = 19.93 r = 18.87 SN Ia z=0.117 ZTF18acrfymv 94.5049 44.1813 11-25 r<19.13 r = 20.05 r = 19.60 S NIc-BL z=0. 072 ZTF18acptgzz 68.3852 -1.6475 11-25 r<19.22 r = 19.01 r = 19.04 SN Ia z=0.096 ZTF18acbyrll 88.8695 29.4723 11-21 r<19.84 r = 18.79 r > 21.87 Asteroid* (1 det) ZTF18acrewzd 70.3221 -1.7688 11-25 r<19.17 r = 20.21 r = 19.9 SN Ia z=0.13 ------------------------------------------------------------------------------------------------------------------------- *Classification from photometric data points. The median 5-sigma upper limit for an isolated point source in ZTF images was r > 20.5 mag for the observations made on November 26 and r > 21.1 mag for the observations made on November 27. ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266 ), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system, supported by NSF PIRE grant 1545949. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23523 SUBJECT: GRB 181126B: KAIT Follow-Up Observations of a Fermi Short GRB (Trigger 564897175) DATE: 18/12/12 19:45:56 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Keto Zhang, Alexei V. Filippenko, and Sergiy Vasylyev (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, observed the field of the short GRB181126B (trigger 564897175) detected by the GBM on the Fermi satellite. More than one thousand galaxies were selected from the Glade catalog (http://aquarius.elte.hu/glade/) according to their priority score. On 2018 Nov. 26 UT, KAIT observed 236 of them having top-priority scores, with each clear-filter exposure time being 60 s. The first image was taken at 07:41:13 UT, about 3.8 hr after the burst, and the last image at 11:51:09 UT. Template images were obtained on 2018 Dec. 8 and 9. The images were processed through the KAIT subtraction pipeline to search for potential optical counterparts. 13 known asteroids were detected, but we found no credible transient that might be the optical afterglow of this GRB. None of the 11 transients reported by Ahumada et al. (GCN 23515) was in the field of view of the KAIT images. Our typical limiting mag is 19.0, although some fields have a shallower limiting mag owing to moonlight.