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.