Beasts of the Southern Wild: Discovery of nine Ultra Faint satellites in the vicinity of the Magellanic Clouds

TL;DR

This paper reports the discovery of nine ultra-faint satellite objects near the Magellanic Clouds using DES data, revealing their likely association with the Clouds and expanding knowledge of the Milky Way's satellite system.

Contribution

First identification of nine new ultra-faint satellites near the Magellanic Clouds using DES data, with implications for their origin and distribution.

Findings

Nine new ultra-faint satellites discovered

Three are dwarf galaxies, one at 380 kpc from the Milky Way

Satellites cluster around the Magellanic Clouds, suggesting past association

Abstract

We have used the publicly released Dark Energy Survey data to hunt for new satellites of the Milky Way in the Southern hemisphere. Our search yielded a large number of promising candidates. In this paper, we announce the discovery of 9 new unambiguous ultra-faint objects, whose authenticity can be established with the DES data alone. Based on the morphological properties, three of the new satellites are dwarf galaxies, one of which is located at the very outskirts of the Milky Way, at a distance of 380 kpc. The remaining 6 objects have sizes and luminosities comparable to the Segue~1 satellite and can not be classified straightforwardly without follow-up spectroscopic observations. The satellites we have discovered cluster around the LMC and the SMC. We show that such spatial distribution is unlikely under the assumption of isotropy, and, therefore, conclude that at least some of the new satellites must have been associated with the Magellanic Clouds in the past.