# Zwicky Transient Facility Science Requirements Document

## Introduction

This document outlines the high-level science requirements of the Zwicky Transient Facility (ZTF), an optical time-domain survey to be based at Palomar Observatory. ZTF is the successor to the Palomar Transient Factory (PTF; 2009–2012) and Intermediate Palomar Transient Factory (iPTF; 2013–present) surveys. PTF and iPTF used a secondhand camera on the Palomar 48-inch Schmidt telescope to survey the sky for astronomical transients and variables. ZTF will instead use a purpose-built survey camera on the same telescope to achieve more than an order of magnitude improvement in survey speed relative to PTF.

## Project Charter

The Zwicky Transient Facility collaboration shall construct an Observing System to be located on the Palomar 48-inch Schmidt Telescope and an associated Data System. These elements will be used to conduct a wide-area, high-cadence time-domain survey in order to discover rare and fast evolving explosive transients, large samples of photometrically variable objects, and solar system bodies.

## Scope

This document outlines the primary science goals of the ZTF project and indicates where these goals lead to specific capability requirements for the ZTF Observing or Data Systems. Detailed discussion of the requirements flow-down and implementation is left to the various Instrument and subsystem Requirements Documents.

TODO: detailed list of CIN for cross-reference.

## Definitions

 Can We use ‘can’ in statements of possibility and capability, whether material, physical, or causal; ‘can’ equates to ‘is able to’ May We use ‘may’ to indicate ‘is permitted to’; it does not represent uncertainty in a requirement (typically indicated through use of ‘TBD’) Shall We use ‘shall’; exclusively to indicate an instrument functional or performance requirement Should We use ‘should’ to indicate an instrument goal Will We use ‘will’ to indicate a statement of fact

## Points of Contact

Eric Bellm, ZTF Project Scientist

## Constraints and Assumptions

\label{sec:constraints}

ZTF will use the Palomar Samuel Oschin 48-inch Schmidt telescope (P48) to survey. While refurbishment of the P48 is within the ZTF project scope, use of the P48 imposes constraints on the ZTF survey.

### Telescope

The Samuel Oschin Telescope provides a $$7^{\circ}\times 7^{\circ}$$ field at 67$${}^{\prime\prime}$$/mm, with some vignetting in the corners. It has a coll