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On the origin of bursts in blue compact dwarf galaxies: clues from kinematics and stellar populations

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Abstract
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 infrared 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 ((nu/sigma)(star)) 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 igniters for our targets.
Keywords
METALLICITY, EVOLUTION, LARGE-SAMPLE, IRREGULAR GALAXIES, ATMOSPHERIC PARAMETERS, VIRGO CLUSTER, ELLIPTIC GALAXIES, DIGITAL SKY SURVEY, STAR-FORMATION HISTORIES, galaxies: stellar content, galaxies: star formation, galaxies: kinematics and dynamics, galaxies: formation, galaxies: dwarf, galaxies: evolution, LIBRARY

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Chicago
Koleva, Mina, Sven De Rijcke, Werner W Zeilinger, Robbert Verbeke, and Joeri Schroyen. 2014. “On the Origin of Bursts in Blue Compact Dwarf Galaxies: Clues from Kinematics and Stellar Populations.” Monthly Notices of the Royal Astronomical Society 441 (1): 452–469.
APA
Koleva, Mina, De Rijcke, S., Zeilinger, W. W., Verbeke, R., & Schroyen, J. (2014). On the origin of bursts in blue compact dwarf galaxies: clues from kinematics and stellar populations. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 441(1), 452–469.
Vancouver
1.
Koleva M, De Rijcke S, Zeilinger WW, Verbeke R, Schroyen J. On the origin of bursts in blue compact dwarf galaxies: clues from kinematics and stellar populations. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. 2014;441(1):452–69.
MLA
Koleva, Mina, Sven De Rijcke, Werner W Zeilinger, et al. “On the Origin of Bursts in Blue Compact Dwarf Galaxies: Clues from Kinematics and Stellar Populations.” MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 441.1 (2014): 452–469. Print.
@article{5750552,
  abstract     = {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 infrared 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 ((nu/sigma)(star)) 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 igniters for our targets.},
  author       = {Koleva, Mina and De Rijcke, Sven and Zeilinger, Werner W and Verbeke, Robbert and Schroyen, Joeri},
  issn         = {0035-8711},
  journal      = {MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY},
  keywords     = {METALLICITY,EVOLUTION,LARGE-SAMPLE,IRREGULAR GALAXIES,ATMOSPHERIC PARAMETERS,VIRGO CLUSTER,ELLIPTIC GALAXIES,DIGITAL SKY SURVEY,STAR-FORMATION HISTORIES,galaxies: stellar content,galaxies: star formation,galaxies: kinematics and dynamics,galaxies: formation,galaxies: dwarf,galaxies: evolution,LIBRARY},
  language     = {eng},
  number       = {1},
  pages        = {452--469},
  title        = {On the origin of bursts in blue compact dwarf galaxies: clues from kinematics and stellar populations},
  url          = {http://dx.doi.org/10.1093/mnras/stu556},
  volume       = {441},
  year         = {2014},
}

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