2007/10/22 by Dolf Michielsen, D. Michielsen, M. Koleva +13 · 3 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Metallicity #Photometry (optics) #Physics #Spectroscopy #Star formation #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/524404
ApJ Letters accepted, 5 pages emulateapj, 2 figures
arxiv created 2007/10/22 · openalex publication_date 2007/10/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present new estimates of ages and metallicities, based on VLT FORS optical (4400-5500 Å) spectroscopy, of 16 dwarf elliptical galaxies (dE's) in the Fornax Cluster and in southern groups. These dE's are more metal-rich and younger than previous estimates based on narrowband photometry and low-resolution spectroscopy. For our sample we find a mean metallicity [ Z /H] = -0.33 dex and mean age 3.5 Gyr, consistent with similar samples of dE's in other environments (Local Group, Virgo). Three dE's in our sample show emission lines and very young ages. This suggests that some dE's formed stars until a very recent epoch and were self-enriched by a long star formation history. Previous observations of large near-infrared (~8500 Å) Ca II absorption strengths in these dE's are in good agreement with the new metallicity estimates, solving part of the so-called calcium puzzle.