Public Data Release 4

ZTF PUBLIC DATA RELEASE 4: Available NOW, December 9, 2020.

The Zwicky Transient Facility (ZTF) and IPAC at the California Institute of Technology announce the fourth ZTF Public Data Release. ZTF is an optical time-domain survey covering the northern sky visible from Palomar Observatory. This release builds upon the third data release to include products from (i) an additional 6 months of survey operations from the public portion of the survey, giving a total observation span of March 2018 - June 2020, and (ii) data acquired under private survey time during the first ~15.4 months of the survey, spanning March 2018 - June 2019. The private surveys include observational programs awarded by Caltech and performed by the ZTF collaboration.

The products include ~18.5 million single-exposure images, ~144,000 co-added images, accompanying source catalog files containing ~296 billion sources extracted from those images, and ~2.7 billion lightcurves constructed from the single-exposure extractions. Note: transient alerts extracted from difference-images commenced public distribution on June 4, 2018. These alerts continue to be generated and distributed as the public survey proceeds.

A guide to ZTF Data Release 4, with data access instructions and supporting documentation is available at https://www.ztf.caltech.edu/page/dr4

Access to the data products is available via the on-line and API services of the NASA/IPAC Infrared Science Archive (IRSA) at https://irsa.ipac.caltech.edu/Missions/ztf.html

ZTF Phase-I (March 2018 - September 2020) was supported by the National Science Foundation and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW.