Deep Extragalactic VIsible Legacy Survey (DEVILS): Motivation, Design and Target Catalogue

TL;DR

DEVILS is a large spectroscopic survey aiming to study galaxies at intermediate redshifts (0.3<z<1.0) with high completeness, using a strategic target selection and feedback approach to optimize observations.

Contribution

This paper introduces the design and target selection strategy of DEVILS, a new spectroscopic survey filling the gap between near and distant universe studies.

Findings

Survey successfully targeted ~60,000 galaxies.

Implemented a feedback strategy to optimize observing efficiency.

Initial spectroscopic observations conducted in late 2017-2018.

Abstract

The Deep Extragalactic VIsible Legacy Survey (DEVILS) is a large spectroscopic campaign at the Anglo-Australian Telescope (AAT) aimed at bridging the near and distant Universe by producing the highest completeness survey of galaxies and groups at intermediate redshifts ($0.3<z<1.0$). Our sample consists of $\sim$60,000 galaxies to Y$<$21.2mag, over $\sim$6deg$^{2}$ in three well-studied deep extragalactic fields (Cosmic Origins Survey field, COSMOS, Extended Chandra Deep Field South, ECDFS and the X-ray Multi-Mirror Mission Large-Scale Structure region, XMM-LSS - all Large Synoptic Survey Telescope deep-drill fields). This paper presents the broad experimental design of DEVILS. Our target sample has been selected from deep Visible and Infrared Survey Telescope for Astronomy (VISTA) Y-band imaging (VISTA Deep Extragalactic Observations, VIDEO and UltraVISTA), with photometry measured by ProFound. Photometric star/galaxy separation is done on the basis of NIR colours, and has been validated by visual inspection. To maximise our observing efficiency for faint targets we employ a redshift feedback strategy, which continually updates our target lists, feeding back the results from the previous night's observations. We also present an overview of the initial spectroscopic observations undertaken in late 2017 and early 2018.