Bibcode
López-Sánchez, A. R.; Esteban, C.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 508, Issue 2, 2009, pp.615-640
Fecha de publicación:
12
2009
Revista
Número de citas
61
Número de citas referidas
56
Descripción
Aims. We have performed a comprehensive multiwavelength analysis of a
sample of 20 starburst galaxies that show the presence of a substantial
population of very young massive stars, most of them classified as
Wolf-Rayet (WR) galaxies. In this paper, the second of the series, we
present the results of the analysis of long-slit intermediate-resolution
spectroscopy of star-formation bursts for 16 galaxies of our sample. Methods: We study the spatial localization of the WR stars in each
galaxy. We analyze the excitation mechanism and derive the reddening
coefficient, physical conditions, and chemical abundances of the ionized
gas. We study the kinematics of the ionized gas to check the
rotation/turbulence pattern of each system. When possible, tentative
estimates of the Keplerian mass of the galaxies are calculated.
Results: Aperture effects and the exact positioning of the slit onto the
WR-rich bursts seem to play a fundamental role in their detection. We
check that the ages of the last star-forming burst estimated using
optical spectra agree with those derived from Hα imagery. Our
analysis shows that a substantial fraction of the galaxies exhibit
evidence of perturbed kinematics. With respect to the results found in
individual galaxies, we remark the detection of objects with different
metallicity and decoupled kinematics in Haro 15 and Mkn 1199, the
detection of tidal streams in IRAS 08208+2816, Tol 9, and perhaps in SBS
1319+579, and the development of a merging process in both SBS 0926+606
A and Tol 1457-262. Conclusions: All of these results - in
combination with those obtained in Paper I - reinforce the hypothesis
that interactions with or between dwarf objects is a very important
mechanism in triggering massive-star formation in starburst galaxies,
especially in dwarf ones. It must be highlighted that only deep and very
detailed observations - as presented in this paper - can provide clear
evidences that these subtle interaction processes are taking place.
Based on observations made with NOT (Nordic Optical Telescope), INT
(Isaac Newton Telescope) and WHT (William Herschel Telescope) operated
on the island of La Palma jointly by Denmark, Finland, Iceland, Norway
and Sweden (NOT) or the Isaac Newton Group (INT, WHT) in the Spanish
Observatorio del Roque de Los Muchachos of the Instituto de
Astrofísica de Canarias.
Table 1 and Figs. 1-4, 6-10, 12, 13, 15-30, 32-35 and Appendix are only
available in electronic form at http://www.aanda.org
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