Bibcode
Cairós, L. M.; Caon, N.; Zurita, C.; Kehrig, C.; Roth, M.; Weilbacher, P.
Bibliographical reference
Astronomy and Astrophysics, Volume 520, id.A90
Advertised on:
9
2010
Journal
Citations
31
Refereed citations
27
Description
Context. Blue compact dwarf (BCD) galaxies are low-luminosity, low-metal
content dwarf systems undergoing violent bursts of star formation. They
present a unique opportunity to probe galaxy formation and evolution and
to investigate the process of star formation in a relatively simple
scenario. Spectrophotometric studies of BCDs are essential to
disentangle and characterize their stellar populations. Aims: We
perform integral field spectroscopy of a sample of BCDs with the aim of
analyzing their morphology, the spatial distribution of some of their
physical properties (excitation, extinction, and electron density) and
their relationship with the distribution and evolutionary state of the
stellar populations. Methods: Integral field spectroscopy
observations of the sample galaxies were carried out with the Potsdam
Multi-Aperture Spectrophotometer (PMAS) at the 3.5 m telescope at Calar
Alto Observatory. An area 16 arcsec × 16 arcsec in size was mapped
with a spatial sampling of 1 arcsec × 1 arcsec. We obtained data
in the 3590-6996 Å spectral range, with a linear dispersion of 3.2
Å per pixel. From these data we built two-dimensional maps of the
flux of the most prominent emission lines, of two continuum bands, of
the most relevant line ratios, and of the gas velocity field. Integrated
spectra of the most prominent star-forming regions and of whole objects
within the FOV were used to derive their physical parameters and the gas
metal abundances. Results: Six galaxies display the same
morphology both in emission line and in continuum maps; only in two
objects, Mrk 32 and Tololo 1434+032, the distributions of the ionized
gas and of the stars differ considerably. In general the different
excitation maps for a same object display the same pattern and trace the
star-forming regions, as expected for objects ionized by hot stars; only
the outer regions of Mrk 32, I Zw 123 and I Zw 159 display higher [S
II]/Hα values, suggestive of shocks. Six galaxies display an
inhomogeneous dust distribution. Regarding the kinematics, Mrk 750, Mrk
206 and I Zw 159 display a clear rotation pattern, while in Mrk 32, Mrk
475 and I Zw 123 the velocity fields are flat.
Tables 3-6 and Figs. 3-9 are only available in electronic form at http://www.aanda.org
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