A deep large binocular telescope view of the Canes Venatici I dwarf galaxy

Nicolas F. Martin, Matthew G. Coleman, Jelte T.A. De Jong, Hans Walter Rix, Eric F. Bell, David J. Sand, John M. Hill, David Thompson, Vadim Burwitz, Emanuele Giallongo, Roberto Ragazzoni, Emiliano Diolaiti, Federico Gasparo, Andrea Grazian, Fernando Pedichini, Jill Bechtold

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Abstract

We present the first deep color-magnitude diagram of the Canes Venatici I (CVn I) dwarf galaxy from observations with the wide-field Large Binocular Camera on the Large Binocular Telescope. Reaching down to the main-sequence turnoff of the oldest stars, it reveals a dichotomy in the stellar populations of CVn I: it harbors an old (≳ 10 Gyr), metal-poor ([Fe/H]∼-2.0), and spatially extended population along with a much younger (∼1.4-2.0 Gyr), 0.5 dex more metal-rich, and spatially more concentrated population. These young stars are also offset by 64+40-20 pc to the east of the galaxy center. The data suggest that this young population, which represents ∼3%-5% of the stellar mass of the galaxy within its half-light radius, should be identified with the kinematically cold stellar component found in a recent spectroscopic survey. CVn I therefore follows the behavior of the other remote MW dwarf spheroidals, which all contain intermediate-age and/or young populations: a complex star formation history is possible in extremely low mass galaxies.

Original languageEnglish (US)
Pages (from-to)L13-L16
JournalAstrophysical Journal
Volume672
Issue number1 PART 2
DOIs
StatePublished - Jan 1 2008

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Keywords

  • Galaxies: individual (Canes Venatici I)
  • Galaxies: stellar content
  • Local Group

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Martin, N. F., Coleman, M. G., De Jong, J. T. A., Rix, H. W., Bell, E. F., Sand, D. J., Hill, J. M., Thompson, D., Burwitz, V., Giallongo, E., Ragazzoni, R., Diolaiti, E., Gasparo, F., Grazian, A., Pedichini, F., & Bechtold, J. (2008). A deep large binocular telescope view of the Canes Venatici I dwarf galaxy. Astrophysical Journal, 672(1 PART 2), L13-L16. https://doi.org/10.1086/525559