The DECam Ecliptic Exploration Project (DEEP): I. Survey description, science questions, and technical demonstration

TL;DR

The DEEP survey uses digital tracking with DECam to discover and characterize thousands of faint trans-Neptunian objects, reaching unprecedented depth and significantly increasing known small TNO populations.

Contribution

This paper introduces the DEEP survey's design, technical approach, and initial results, notably the use of digital tracking to detect extremely faint TNOs beyond previous survey limits.

Findings

Detected TNOs as faint as VR~27 mag, 2.5 magnitudes deeper than standard surveys.

More than doubled the known TNOs with 24+ hour observational arcs.

Increased the count of small (<50 km) TNOs by over tenfold.

Abstract

We present here the DECam Ecliptic Exploration Project (DEEP), a three year NOAO/NOIRLab Survey that was allocated 46.5 nights to discover and measure the properties of thousands of trans-Neptunian objects (TNOs) to magnitudes as faint as VR~27, corresponding to sizes as small as 20 km diameter. In this paper we present the science goals of this project, the experimental design of our survey, and a technical demonstration of our approach. The core of our project is "digital tracking," in which all collected images are combined at a range of motion vectors to detect unknown TNOs that are fainter than the single exposure depth of VR~23 mag. Through this approach we reach a depth that is approximately 2.5 magnitudes fainter than the standard LSST "wide fast deep" nominal survey depth of 24.5 mag. DEEP will more than double the number of known TNOs with observational arcs of 24 hours or more, and increase by a factor of 10 or more the number of known small (<50 km) TNOs. We also describe our ancillary science goals, including measuring the mean shape distribution of very small main belt asteroids, and briefly outline a set of forthcoming papers that present further aspects of and preliminary results from the DEEP program.