Understanding the physical processes that lead galaxies to stop making stars at one point in their evolution is a major goal of the GOYA Survey. The onset of the galaxy red sequence came hand in hand with the appearance of morphologically regular galaxies, and, roughly, coincides with the start of the decline of the SFR density of the Universe at 1<z<2, and increase of the typical stellar mass of the red galaxies.Our samples will be selected in baryonic mass, or rest-frame K-band luminosity, on fields with HST imaging. Color-color criteria will be used to preselect galaxies in the range 1<z<2. EMIR will provide Hα emission as well as absorption line spectroscopy of the brightest targets; we will cover the rest-frame 5000 Å region that includes Hβ, Mg, and several Fe lines, which project onto the middle of the J band at z=1.5. With a spectral resolution of R=4000, we will be able to map the absorption lines through the forest of OH telluric lines. Mg and Fe indices will provide information on the ages and metallicities of the stellar populations. On fainter targets, the 4000 Å break will provide an additional age indicator. The multiplex capability of EMIR makes long integrations practical. These will provide a representative sample of galaxies with measurements of absorption line indices and velocity dispersions.
last updated on March 2008 by jorG
Driver et al. 1998
© J. Pérez-Gallego & R. Guzmán