[vsnet-grb-info 24568] IceCube-200107A: No candidates from the Zwicky Transient Facility

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26667
SUBJECT: IceCube-200107A: No candidates from the Zwicky Transient Facility
DATE:    20/01/08 14:16:06 GMT
FROM:    Robert Stein at DESY  <robert.stein at desy.de>

Robert Stein and Simeon Reusch (DESY) report,

On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: 

We observed the localization region of the neutrino event IceCube-200107A (Stein et al., GCN 26655) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We first started observations serendipitously in the g-band and r-band beginning at 2020-01-07T11:42:04.700 UTC, approximately 2.0 hours after event time. We covered 6.3 sq deg, corresponding to 84.2% of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. 

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). AMPEL (Nordin et al. 2019) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019). We find no high-significance transient or variable candidates with our pipeline. 

We will continue to observe this field to search for new transients.

ZTF and GROWTH are worldwide collaborations comprising 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.