{
  "bibcode": "2019GCN.24257....1G",
  "body": "Daniel A. Goldstein (Caltech), Igor Andreoni (Caltech), Michael\nCoughlin (Caltech), Mansi M. Kasliwal (Caltech), Peter E. Nugent\n(LBNL), Joshua S. Bloom (UC Berkeley), Keming Zhang (UC Berkeley),\nShreya Anand (Caltech), Jennifer Barnes (Columbia), S. Bradley Cenko\n(NASA GSFC), Jeffrey Cooke (Swinburne), Jorge Mart��nez Palomera (UC\nBerkeley), Leo P. Singer (NASA GSFC), on behalf of the Global Relay of\nObservatories Watching Transients Happen (GROWTH) and ZTF\ncollaborations:\n\nWe are observing the ecliptic lobe and southern regions of the\nnorthern lobe of the localization region of the gravitational wave\ntrigger S190426c (LIGO Scientific Collaboration and the Virgo\nCollaboration, GCN #24237) with the Victor M. Blanco 4m Telescope at\nCerro Tololo Inter-American Observatory, equipped with the Dark Energy\nCamera (DECam). An observational tiling for the event was\nautomatically and optimally determined and triggered using the GROWTH\nTarget of Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al.\n2019b). We plan to observe 35% of the integrated probability and more\nthan 800 square degrees with 30 second visits in r and 50 in z. Our\nlimiting magnitudes are expected to be ~22.9 in r and ~22.4 in z,\nbased on the DECam exposure time calculator\n(http://www.ctio.noao.edu/noao/sites/default/files/DECam/DECam_ETC-ARW-RCS7.xls).\n\nThe data from this program are immediately public and we invite anyone\ninterested to search the images for optical counterparts. We are\nsearching the images in real time for optical counterpart candidates\nusing an image subtraction pipeline written for this program. We\ninvite anyone interested to download the images. The images are\navailable under proposal ID 2019A-0205 from the NOAO archive\n(archive.noao.edu). For any questions on the data or the observations,\nplease contact the PIs of this program, Danny Goldstein and Igor\nAndreoni (danny@caltech.edu, andreoni@caltech.edu).\n\nGROWTH and ZTF are worldwide collaborations comprising Caltech, USA;\nIPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA;\nDESY, Germany; MOST, Taiwan; UW Milwaukee, USA; TTU, USA; LANL USA;\nTokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, UK and USyd,\nAustralia. ZTF acknowledges the generous support of the NSF under AST\nMSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF\nunder PIRE Grant No 1545949. Alert distribution service provided by\nDIRAC@UW (Patterson et al. 2019). Alert filtering and follow-up\nco-ordination is being undertaken by the GROWTH marshal system\n(Kasliwal et al. 2019).",
  "circularId": 24257,
  "createdOn": 1556329095000,
  "email": "danny@caltech.edu",
  "subject": "LIGO/Virgo S190426c: Public DECam Observations",
  "submitter": "Daniel Goldstein at Caltech  <danny@caltech.edu>",
  "eventId": "LIGO/Virgo S190426c"
}