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Title: A near-infrared census of the multicomponent stellar structure of early-type dwarf galaxies in the Virgo cluster

The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we study a nearly magnitude-complete sample (–19 < M{sub r} < –16 mag) of 121 Virgo cluster early types with deep near-infrared images from the SMAKCED project. We fit two-dimensional models with optional inner and outer components, as well as bar and lens components (in ∼15% of the galaxies), to the galaxy images. While a single Sérsic function may approximate the overall galaxy structure, it does not entirely capture the light distribution of two-thirds of our galaxies, for which multicomponent models provide a better fit. This fraction of complex galaxies shows a strong dependence on luminosity, being larger for brighter objects. We analyze the global and component-specific photometric scaling relations of early-type dwarf galaxies and discuss similarities with bright early and late types. The dwarfs' global galaxy parameters show scaling relations that are similar to those of bright disk galaxies. The inner components are mostly fitted withmore » Sérsic n values close to 1. At a given magnitude, they are systematically larger than the bulges of spirals, suggesting that they are not ordinary bulges. We argue that the multicomponent structures in early-type dwarfs are mostly a phenomenon inherent to the disks and may indeed stem from environmental processing.« less
Authors:
; ;  [1] ; ; ; ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6] ; ;  [7] ;  [8]
  1. Division of Astronomy, Department of Physics, P.O. Box 3000, FI-90014 University of Oulu (Finland)
  2. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany)
  3. Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands)
  4. Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)
  5. UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
  6. University of Vienna, Department of Astrophysics, Türkenschanzstraße 17, 1180 Vienna (Austria)
  7. Instituto de Astrofísica de Canarias, Vía Láctea s/n, La Laguna, Tenerife (Spain)
  8. CNRS, LAM (Laboratoire d'Astrophysique de Marseille) UMR 7326, Aix Marseille Université, F-13388 Marseille (France)
Publication Date:
OSTI Identifier:
22356915
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; CAPTURE; DENSITY; DISTRIBUTION; GALAXIES; GALAXY CLUSTERS; GRAVITATIONAL LENSES; IMAGES; LUMINOSITY; PHOTOMETRY; SCALING; STARS; TWO-DIMENSIONAL CALCULATIONS; VISIBLE RADIATION