Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: The study of stellar populations in early-type galaxies in differentenvironments is a powerful tool for constraining their star formationhistories. This study has been traditionally restricted to the optical range,where dwarfs around the turn-off and stars at the base of the RGB dominate theintegrated light at all ages. The near-infrared spectral range is especiallyinteresting since in the presence of an intermediate-age population, AGB starsare the main contributors. In this letter, we measure the near-infrared indicesNaI and D$ { m CO}$ for a sample of 12 early-type galaxies in low densityenvironments and compare them with the Fornax galaxy sample presented by Silvaet al. 2008. The analysis of these indices in combination with Lick-IDSindices in the optical range reveals i the NaI index is a metallicityindicator as good as C4668 in the optical range, and ii D$ { m CO}$ is atracer of intermediate-age stellar populations. We find that low-mass galaxiesin low density environments show higher NaI and D$ { m CO}$ than those locatedin Fornax cluster, which points towards a late stage of star formation for thegalaxies in less dense environments, in agreement with results from otherstudies using independent methods.



Author: E. Mármol-Queraltó, N. Cardiel, P. Sánchez-Blázquez, S.C. Trager, R.F. Peletier, H. Kuntschner, D.R. Silva, A.J. Cenarro, A.

Source: https://arxiv.org/



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