Digital Sky Surveys from the ground: Status and Perspectives

TL;DR

This paper reviews the current status and future perspectives of ground-based digital sky surveys, focusing on extragalactic imaging surveys, their properties, overlaps, and the challenges faced in the Southern Hemisphere.

Contribution

It provides a comprehensive comparison of major extragalactic sky surveys, especially highlighting the properties of the VST ATLAS and the evolving landscape of multiwavelength imaging.

Findings

Southern Hemisphere surveys will soon surpass Northern ones in multiwavelength coverage

Limited spectroscopic follow-up opportunities in the South will persist during LSST era

The South's imaging capabilities are expanding faster than spectroscopic resources

Abstract

I first review the status of Digital Sky Surveys. The focus will be on extragalactic surveys with an area of more than 100 sq.deg. The Sloan Digital Sky Survey is the archetype of such imaging surveys and it is its great success that has prompted great activity in this field. The latest surveys explore wider, fainter and higher resolution and also a longer wavelength range than SDSS. Many of these surveys overlap particularly in the S Hemisphere where we now have Pan-STARRS, DES and the ESO VST surveys, and our aim here is to compare their properties. Since there is no dedicated article on the VST ATLAS in this symposium, we shall especially review the properties of this particular survey. This easily fits onto our other main focus which is to compare overlapping Southern Surveys and see how they best fit with the available NIR imaging data. We conclude that the Southern Hemisphere will soon overtake the North in terms of multiwavelength imaging. However we note that the South has more limited opportunities for spectroscopic follow-up and this weakness will persist during the LSST era. Some new perspectives are offered on this and other aspects of survey astronomy.