On the origin of bursts in blue compact dwarf galaxies: clues from kinematics and stellar populations
| Autor: | J. Schroyen, M. Koleva, Robbert Verbeke, Ww Zeilinger, L. Vermeylen, S. De Rijcke |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
LARGE-SAMPLE
formation [galaxies] dwarf [galaxies] FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Galaxy merger IRREGULAR GALAXIES ATMOSPHERIC PARAMETERS ELLIPTIC GALAXIES kinematics and dynamics [galaxies] Astrophysics::Solar and Stellar Astrophysics Interacting galaxy Lenticular galaxy evolution [galaxies] Astrophysics::Galaxy Astrophysics STAR-FORMATION HISTORIES Dwarf galaxy Physics Astronomy Astronomy and Astrophysics stellar content [galaxies] VIRGO CLUSTER Astrophysics - Astrophysics of Galaxies EVOLUTION Galaxy Dwarf spheroidal galaxy Physics and Astronomy Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Globular cluster LIBRARY Elliptical galaxy DIGITAL SKY SURVEY Astrophysics::Earth and Planetary Astrophysics star formation [galaxies] METALLICITY |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY |
| ISSN: | 0035-8711 |
| Popis: | Blue compact dwarf galaxies (BCDs) form stars at, for their sizes, extraordinarily high rates. In this paper, we study what triggers this starburst and what is the fate of the galaxy once its gas fuel is exhausted. We select four BCDs with smooth outer regions, indicating them as possible progenitors of dwarf elliptical galaxies. We have obtained photometric and spectroscopic data with the FORS and ISAAC instruments on the VLT. We analyse their infra-red spectra using a full spectrum fitting technique which yields the kinematics of their stars and ionized gas together with their stellar population characteristics. We find that the_stellar_ velocity to velocity dispersion ratio (v/sigma) of our BCDs is of the order of 1.5, similar to that of dwarf elliptical galaxies. Thus, those objects do not require significant (if any) loss of angular momentum to fade into early type dwarfs. This finding is in discordance with previous studies, which however compared the stellar kinematics of dwarf elliptical galaxies with the gaseous kinematics of star forming dwarfs. The stellar velocity fields of our objects are very disturbed and the star-formation regions are often kinematically decoupled from the rest of the galaxy. These regions can be more or less metal rich with respect to the galactic body, and sometimes they are long lived. These characteristics prevent us from pinpointing a unique trigger of the star formation, even within the same galaxy. Gas impacts, mergers, and in-spiraling gas clumps are all possible star-formation ignitors for our targets. 20 pages, 13 fig, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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