Kinematics and physical properties of Southern interacting galaxies: the minor merger AM 2306-721 - AstrophysicsReportar como inadecuado

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Abstract: We present an observational study about the effects of the interactions inthe kinematics, stellar population and abundances of the components of thegalaxy pair AM2306-721. Rotation curves for the main and companion galaxieswere obtained, showing a deprojected velocity amplitude of 175 km-s and 185km-s, respectively. The interaction between the main and companion galaxies wasmodeled using numerical N-body-hydrodynamical simulations, with the resultindicating that the current stage of the merger would be about 250 Myr afterperigalacticum. The spatial variation in the distribution of the stellarpopulation components in both galaxies was analysed by fitting combinations ofstellar population models of different age groups. The central region of maingalaxy is dominated by an old 5-10 Gyr population, while significantcontributions from a young 200 Myr and intermediate 1 Gyr components arefound in the disk, being enhanced in the direction of the tidal features. Thestellar population of the companion galaxy is overall much younger, beingdominated by components with 1 Gyr or less, quite widely spread over the wholedisk. Spatial profiles of the oxygen abundance were obtained from the a grid ofphotoionization models using the R23 line ratio. The disk of the main galaxyshows a clear radial gradient, while the companion galaxy presents an oxygenabundance relatively homogeneous across the disk. The absence of an abundancegradient in the secondary galaxy is interpreted in terms of mixing by gas flowsfrom the outer parts to the center of the galaxy due to the gravitationalinteraction with the more massive primary.

Autor: A.C.Krabbe, M.G.Pastoriza, Claudia Winge, I.Rodrigues, D.L.Ferreiro


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