Siriusly, a newly identified intermediate-age Milky Way stellar cluster: a spectroscopic study of Gaia 1. - Simpson, J. D.; De Silva, G. M.; Martell, S. L.; Zucker, D. B.; Ferguson, A. M. N.; Bernard, E. J.; Irwin, M.; Penarrubia, J.; Tolstoy, E. (Monthly Notices of the Royal Astronomical Society, 2017)