Identification of an [α/Fe]—Enhanced Thick Disk Component in an Edge-on Milky Way Analog

Abstract The Milky Way disk consists of two prominent components—a thick, alpha-rich, low-metallicity component and a thin, metal-rich, low-alpha component. External galaxies have been shown to contain thin- thick-disk components, but whether distinct components in the [ α /Fe]–[Z/H] plane exist other Way-like is not yet known. We present Very Large Telescope (VLT)—Multi Unit Spectroscopic Explorer (MUSE) observations UGC 10738, nearby, edge-on galaxy. demonstrate through stellar population synthesis model fitting that 10738 contains alpha-rich alpha-poor populations with similar spatial distributions same Way. discuss how finding external also chemically may act as significant constraint on formation Way’s own thin thick disk.