TITLE:   GCN CIRCULAR
NUMBER:  26662
SUBJECT: LIGO/Virgo S200105ae: Upper Limits from the Zwicky Transient Facility
DATE:    20/01/07 21:15:51 GMT
FROM:    Shreya Anand at GROWTH Caltech  <sanand@caltech.edu>

S. Anand (Caltech), M. Coughlin (U Minn), L. Singer (NASA GSFC), D. Goldstein (Caltech), I. Andreoni (Caltech), M. M. Kasliwal (Caltech), E. Bellm (U Washington), T. Ahumada (UMD), S. B. Cenko (NASA GSFC), S. Nissanke (UVA), V. Bhalerao (GROWTH-India), E. Kool (OKC), R. Stein (DESY), S. Reusch (DESY) report on behalf of the GROWTH Collaboration:

We observed the localization region of the gravitational wave trigger S200105ae (LVC, GCN #26640) with the Palomar 48-inch telescope equipped with the 47 square degree Zwicky Transient Facility camera (ZTF, Bellm et al. 2019, Graham et al. 2019).

The tiling was optimally determined and triggered using the GROWTH Target of Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al. 2019b). We started obtaining target-of-opportunity observations in the g-band and r-band beginning at 2020-01-07 01:54 UT. Combining triggered 180s and serendipitous 30s observations, we covered 45.1% of the enclosed probability with a median depth of 19.5 mag (due to poor seeing conditions and proximity to the moon). 

The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). Alert filtering and follow-up coordination was undertaken by the GROWTH Marshal system (Kasliwal et al. 2019). The ZTF alert stream was also queried using the Kowalski infrastructure (Duev et al., 2019) and with AMPEL (Nordin et al. 2019).

No candidates of interest have been identified thus far. Additional analysis is in progress.

ZTF and GROWTH are worldwide collaborations comprising of Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019).