Projects
The Quarter Century Sky: Data Reduction and Timescale Analysis On Transient Sky Surveys
A Photometry Pipeline and a User Interface for Automated Data Reduction, Long Timescale Analysis, and Data Visualization.
PI: Matthew J. Graham (Division of Physics, Mathematics, and Astronomy) and Thomas A. Prince (Division of Physics, Mathematics, and Astronomy)
SASE: Shinn Taniya, Scholar
The theoretical and practical schedule problem regarding methods to best sequence astrophysical observations for maximum scientific output is challenging. On a typical night or season, the potential number of observing sequences is combinatorically large and encounters further complications from observing conditions as Target of Opportunity (TOO) observations require facilities to adapt to transient phenomena. Further, the quality of potential observations may vary with time as observations may have sequential relationships that weather losses and other limitations can complicate. Thus, traditionally, sky survey data was collected through the manual involvement of human observers, but manual scheduling introduces significant drawbacks.
Several projects have implemented sophisticated schedulers to deliver semi-automated, global optimization solutions to reduce manual scheduling issues. Applying an integer linear programming algorithm for scheduling, the Zwicky Transient Facility (ZTF) has yielded an order of magnitude improvement in survey speed and adaptability compared to its predecessors. Reusing and improving the conceptual design of the Palomar 48-inch Samuel Oschin Schmidt Telescope, enables the identification of transients at high observing cadence within a significant fraction of the accessible night sky. ZTF’s real-time alert system and analysis infrastructure enables large sequences of observations, essential for organizing and analyzing space-time patterns. As sizeable digital sky surveys such as ZTF start to represent a fundamental data basis for astronomy, it is increasingly clear that the design and implementation of a more efficient, consistent, and standardized archive architecture that can handle data from a wide variety of sky surveys are essential.
Through the Quarter Century Sky Project, ZTF researchers collaborated with the Schmidt Academy to extend the ZTF infrastructure by constructing an archive with a photometry data reduction pipeline, API, and a front-end UI to enable extended timescale analysis and data visualization of astronomical objects. The work standardized and combined time series from prominent sky surveys, including the Catalina Real-Time Survey and the Palomar Transient Factory, to offer temporal baselines for observational astronomy from 4 to 25 years. The work helped to open a deeper understanding of astronomical phenomena on decade timescales with systematic studies that are not currently possible.
Figure 1: Table demonstrating ZTF’s improved performance compared to its predecessor, the Palomar Transient Factory (PTF)
Figure 2: Overall data and processing flow in the ZSDS. Green components indicate storage in the form of an archive and/or database residing at IPAC to serve either the public or internal (private) collaboration. Vermillion (light brown) components represent the core pipelines. Blue components indicate external interfaces or dependencies.