The Dragonfly Wide Field Survey. I. Telescope, Survey Design and Data Characterization

TL;DR

The Dragonfly Wide Field Survey uses a specialized telescope to map low surface brightness features over a large sky area, aiming to study dwarf galaxies beyond the Local Group with unprecedented depth and sensitivity.

Contribution

This paper introduces the survey design, telescope setup, and data processing pipeline, enabling detection of faint, extended low surface brightness structures.

Findings

Achieved 1σ depths of ~31 mag arcsec$^{-2}$ in g-band.

Detected Milky Way satellites out to ~10 Mpc.

Demonstrated the telescope's capability for low surface brightness detection.

Abstract

We present a description of the Dragonfly Wide Field Survey (DWFS), a deep photometric survey of a wide area of sky. The DWFS covers 330 $\mathrm{deg}^2$ in the equatorial GAMA fields and the Stripe 82 fields in the SDSS $g$ and $r$ bands. It is carried out with the 48-lens Dragonfly Telephoto Array, a telescope that is optimized for the detection of low surface brightness emission. The main goal of the survey is to study the dwarf galaxy population beyond the Local Group. In this paper, we describe the survey design and show early results. We reach $1\sigma$ depths of $\mu_g\approx 31$ mag arcsec$^{-2}$ on arcminute scales and show that Milky Way satellites such as Sextans, Bootes, and Ursa Major should be detectable out to $D\gtrsim 10$ Mpc. We also provide an overview of the elements and operation of the 48-lens Dragonfly telescope and a detailed description of its data reduction pipeline. The pipeline is fully automated, with individual frames subjected to a rigorous series of quality tests. The sky subtraction is performed in two stages, ensuring that emission features with spatial scales up to $\sim 0.^{\circ}9 \times 0.^{\circ}6$ are preserved. The DWFS provides unparalleled sensitivity to low surface brightness features on arcminute scales.