Enabling Synergistic Science between the Rubin Observatory and the Zwicky Transient Facility

Time-domain astronomy is one of the four science pillars of Vera C. Rubin Observatory, which is co-funded by the NSF and set to start survey operations in 2025. Over the past six years, the Zwicky Transient Facility (ZTF), a mid-scale observatory led by California Institute of Technology and largely funded by the NSF, has served as the training ground for the time-domain community across a breadth of astrophysics.

This research program will provide at least one year of joint ZTF+Rubin operations to facilitate synergistic science, multiplying the science return of what either survey can do independently. The data produced from nightly joint operations will yield important science results, along with the necessary training to apply transfer learning using advanced machine learning algorithms.

The broader societal impact program focuses on mentoring: graduate students for PhDs, postdoctoral scholars, undergraduate students for summer projects and senior theses, and high school students and high school teachers for summer projects. The public outreach plan includes a Pokemon-style mobile app called ZARTH, the Palomar Observatory visitor center, public lectures and timely media articles reporting the newest discoveries.

This research award is partially funded by a generous gift from Charles Simonyi to the NSF Astronomy division. The project includes significant contributions to Vera C. Rubin Observatory’s Legacy Survey of Space and Time. This project is also relevant to Windows on the Universe: Multi-Messenger Astrophysics.

The intellectual merit of joint ZTF+Rubin operations spans all facets of time-domain astronomy. ZTF will observe the accessible Rubin footprint (11K sq deg) twice a night every night. Every month, for two nights, ZTF will do a continuous cadence exercise on the Rubin deep drilling fields.

Joint ZTF+Rubin operations for at least one year will yield over 1500 spectroscopically classified supernovae detected by both surveys that can squarely address the power source, mass-loss history and luminosity function questions. The majority of these supernovae will be Type Ia and joint detections will yield the necessary calibration with the precision needed for cosmology.

Large samples of rare classes of transients such as tidal disruption flares will be uncovered. Compact white dwarf binaries will be found in the Rubin footprint, which can be thoroughly characterized in preparation for the LISA gravitational wave mission. Joint ZTF+Rubin data may even enable serendipitous discovery of a few kilonovae even while the gravitational wave interferometers are offline.

Overall, concurrent ZTF operations will amplify early science with Rubin in the very first year of operations and lay the transfer learning groundwork to maximize the time-domain science for the rest of the decade.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.