Projeto Observacional para 2015B - SO2015B-018

Autor: Basílio X. Santiago
Instituição: UFRGS
e-mail: santiago@if.ufrgs.br

Co-autores:
Alex Wagner
Keith Bechtol
Brian Yanny
Luiz Nicolaci da Costa
Alistair Walker
D.J. James
Marcio A.G. Maia
Elmer Luque
Adraino Pires

Título: Imaging Follow-up of Milky-Way companions revealed by the Dark Energy Survey

Resumo: Understanding the properties of the remaining system of Milky-Way satellite galaxies is a necessary step towards modelling the process of Galactic mass assembly, constraining the number of dark matter rich MW subhalos and testing scenarios of structure formation. We propose to obtain SOAR/SOI follow up data for 14 Galactic companion candidates found with the first internal data release of the Dark Energy Survey and whose initial distance estimates place them at < 90 kpc. The gri photometry down to g ~ 25, i ~ 24 will reach below the main sequence turn-off of the most conspicuous candidates and allow for a more accurate determination of their sizes, ages, metallicities, luminosities and distances. Systems with a range of stellar ages and metallicities are more likely to be dwarf galaxies than star clusters. The requested data will also confirm the physical nature and allow for characterization of the more sparsely populated systems in the sample. When coupled with spectroscopy, the SOAR data will also yield better estimates of their mass-to-light ratios and dark matter content.