The merging system AM 2049-691

Citation
El. Aguero et al., The merging system AM 2049-691, PUB AST S P, 113(790), 2001, pp. 1515-1521
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
113
Issue
790
Year of publication
2001
Pages
1515 - 1521
Database
ISI
SICI code
0004-6280(200112)113:790<1515:TMSA2>2.0.ZU;2-6
Abstract
We present photometric and spectroscopic observations of the peculiar objec t AM 2049-691, whose most remarkable features are (1) two distinct nuclei c onnected by a bridge and (2) two tails. We studied seven zones and found th at they have spectral features typical of H II regions of low excitation, e lectron temperatures and densities in the range of normal values for such r egions, and quite high internal reddening. The derived H alpha + N II equiv alent widths suggest enhanced star formation when a comparison is made with isolated galaxies, especially in the northeast nucleus; the equivalent wid th of the integrated spectrum reflects starburst activity in the whole obje ct, which is compatible with a merger of two disk galaxies. We detected a c omparative overabundance of nitrogen relative to oxygen in the southwest nu cleus, which has the most evolved population. The bridge between the nuclei was also observed in H alpha emission. B-V colors of the nuclei, after cor rection for internal absorption, also indicate that they are star-forming r egions. The central radial velocity dispersions at the nuclei suggest that the most massive galaxy might be the progenitor of the southwest component. The observed radial velocity distribution shows the presence of two subsys tems, each one associated with a different nucleus.