Gemini Frontier Fields: Wide-field Adaptive Optics $K_s$-band Imaging of the Galaxy Clusters MACS J0416.1-2403 and Abell 2744

TL;DR

This paper presents high-resolution, wide-field Ks-band imaging of two galaxy clusters using advanced adaptive optics, enhancing the observational capabilities for studying distant universe structures beyond HST's reach.

Contribution

It demonstrates the effectiveness of Gemini's multi-conjugate adaptive optics system in achieving near-diffraction-limited imaging over large fields, complementing space-based observations.

Findings

Achieved 0.08-0.10 arcsecond resolution over 100x100 arcsecond fields.

Reaches a 5 sigma depth of Ks=25.6 mag for compact sources.

Provides fully calibrated, high-quality images for public use.

Abstract

We have observed two of the six Frontier Fields galaxy clusters, MACS J0416.1-2403 and Abell 2744, using the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI). With 0.08"-0.10" FWHM our data are nearly diffraction-limited over a 100"x100" wide area. GeMS/GSAOI complements the Hubble Space Telescope (HST) redwards of 1.6microns with twice the angular resolution. We reach a 5 sigma depth of Ks = 25.6 mag (AB) for compact sources. In this paper we describe the observations, the data processing and the initial public data release. We provide fully calibrated, co-added images matching the native GSAOI pixel scale as well as the larger plate scales of the HST release, adding to the legacy value of the Frontier Fields. Our work demonstrates that even for fields at high galactic latitude, where natural guide stars are rare, current multi-conjugated adaptive optics technology at 8m-telescopes has opened a new window on the distant Universe. Observations of a third Frontier Field, Abell 370, are planned.