A1 Refereed original research article in a scientific journal
A Near-infrared Census of the Multicomponent Stellar Structure of Early-type Dwarf Galaxies in the Virgo cluster
Authors: Janz J., Laurikainen E., Lisker T., Salo H., Peletier R. F.,Niemi S. M., Toloba E., Hensler G., Falc\'on-Barroso J., Boselli A., den Brok M., Hansson K. S. A., Meyer H. T., R\'ys A., Paudel S.
Publisher: Institute of Physics (IOP)
Publishing place: McMaster University, 1280 Main Street West, GSB-118C, Hamilton, ON L8S 4K1
Publication year: 2014
Journal:Astrophysical Journal
Journal acronym: ApJ
Volume: 786
Issue: 2
First page : 120
Last page: 131
Number of pages: 12
ISSN: 0004-637X
DOI: https://doi.org/10.1088/0004-637X/786/2/105
 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 < Mr < 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 S\'ersic 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 with S\'ersic 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.
