The Zwicky Transient Facility: Science Objectives (1902.01945v1)

Abstract: The Zwicky Transient Facility (ZTF), a public-private enterprise, is a new time domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg$^2$ field of view and 8 second readout time. It is well positioned in the development of time domain astronomy, offering operations at 10% of the scale and style of the Large Synoptic Survey Telescope (LSST) with a single 1-m class survey telescope. The public surveys will cover the observable northern sky every three nights in g and r filters and the visible Galactic plane every night in g and r. Alerts generated by these surveys are sent in real time to brokers. A consortium of universities which provided funding ("partnership") are undertaking several boutique surveys. The combination of these surveys producing one million alerts per night allows for exploration of transient and variable astrophysical phenomena brighter than r $\sim$ 20.5 on timescales of minutes to years. We describe the primary science objectives driving ZTF including the physics of supernovae and relativistic explosions, multi-messenger astrophysics, supernova cosmology, active galactic nuclei and tidal disruption events, stellar variability, and Solar System objects.

• The paper demonstrates ZTF's main contribution by detailing its rapid, large-scale transient detection using a 576-megapixel camera.
• It employs a high-cadence scanning strategy every three nights, enabling comprehensive follow-up observations of supernovae and other transients.
• Its innovative alert system, generating up to one million nightly alerts, paves the way for breakthroughs in multi-messenger astronomy and future surveys.

An Overview of the Zwicky Transient Facility: Science Objectives

The Zwicky Transient Facility (ZTF) is a pivotal astronomical survey aimed at exploring the dynamic sky. Operated with a 576-megapixel camera on the Palomar 48" Schmidt telescope, ZTF scans a vast sky area with rapid cadence, significantly contributing to the domain of time-domain astronomy. This paper outlines the scientific objectives driving ZTF's mission and discusses its broad spectrum of potential discoveries, ranging from supernovae (SNe) to solar system objects.

A central strength of ZTF lies in its rapid, large-scale survey capability, observing the northern sky every three nights. It alerts the astronomical community to transients in real-time using a high-efficiency alert distribution system. This unprecedented alert volume—about one million per night—enables extensive studies of transient phenomena bright as $r \sim 20.5$.

Science Goals and Observational Strategies

ZTF's primary science goals encompass several domains:

1. Supernovae and Relativistic Explosions: ZTF aims to discover and paper young supernovae and transient phenomena by focusing on high-cadence sky observations. This includes exploring the early phases of Type Ia and core-collapse supernovae. The paper of infant supernovae can elucidate shock breakout and progenitor characteristics, especially when paired with rapid spectroscopic follow-up using the Palomar 60-inch telescope.
2. Multi-Messenger Astrophysics: ZTF enhances multi-messenger astronomy by seeking electromagnetic counterparts to high-energy neutrinos, gamma-ray bursts, and gravitational wave events. It efficiently allocates target-of-opportunity observations to provide temporal data critical for validating multi-messenger signals.
3. Cosmological Studies: By monitoring Type Ia supernovae frequency and brightness, ZTF contributes to measuring cosmic expansion. Furthermore, ZTF’s extensive coverage helps detect gravitationally-lensed supernovae, offering independent means of constraining cosmological parameters, such as the Hubble constant.
4. Active Galactic Nuclei and Tidal Disruption Events: ZTF assists in tracking active galactic nuclei variability and uncovering tidal disruption events by leveraging its high temporal resolution and survey depth. Early identification and characterization of these events provide insights into black hole accretion processes.
5. Galactic and Solar System Science: ZTF surveys yield data crucial for understanding stellar variability, binary stars, and small solar system bodies' dynamics, providing detailed light curves and enabling the detection of rare transient events in our solar system.
6. Astroinformatics and Astrostatistics: ZTF data facilitates the development of new analytical techniques, preparing methodologies applicable to even larger datasets from future surveys like LSST.

Implications and Future Directions

ZTF serves as a pathfinder for future large-scale surveys, notably the Large Synoptic Survey Telescope (LSST). Its alert system trial tests critical for handling large datasets that will become routine with LSST’s scale. Moreover, ZTF supports growth in the open science paradigm by distributing its data pipeline outputs, which will inspire new tools and skills required for future astronomical surveys.

Conclusively, ZTF is set to redefine transient astronomy through its comprehensive observation strategies and innovative follow-up capacities, thus significantly impacting our understanding of the dynamic universe.