Bibcode
Eliche-Moral, M. C.; González-García, A. C.; Aguerri, J. A. L.; Gallego, J.; Zamorano, J.; Balcells, M.; Prieto, M.
Bibliographical reference
Astronomy and Astrophysics, Volume 547, id.A48, 12 pp.
Advertised on:
11
2012
Journal
Citations
30
Refereed citations
30
Description
Context. Recent studies have argued that galaxy mergers are not
important drivers for the evolution of S0's, on the basis that mergers
cannot preserve the coupling between the bulge and disk scale-lengths
observed in these galaxies and the lack of correlation of their ratio
with the S0 Hubble type. However, about 70% of present-day S0's reside
in groups, an environment where mergers and tidal interactions dominate
galaxy evolution. Aims: We investigate whether the remnants
resulting from collision-less N-body simulations of intermediate and
minor mergers onto S0 galaxies evolve fulfilling global structural
relations observed between the bulges and disks of these galaxies. Methods: Different initial bulge-to-disk ratios of the primary S0
have been considered, as well as different satellite densities, mass
ratios, and orbits of the encounter. We have analysed the final
morphology of the remnants in images simulating the typical observing
conditions of S0 surveys. We derive bulge + disk decompositions of the
final remnants to compare their global bulge-to-disk structure with
observations. Results: We show that all remnants present
undisturbed S0 morphologies according to the prescriptions of
specialized surveys. The dry intermediate and minor mergers induce
noticeable bulge growth (S0c → S0b and S0b → S0a), but affect
negligibly to the bulge and disk scale-lengths. Therefore, if a coupling
between these two components exists prior to the merger, the encounter
does not break this coupling. This fact provides a simple explanation
for the lack of correlation between the ratio of bulge and disk
scale-lengths and the S0 Hubble type reported by observations.
Conclusions: These models prove that dry intermediate and minor mergers
can induce global structural evolution within the sequence of S0 Hubble
types compatible with observations, meaning that these processes should
not be discarded from the evolutionary scenarios of S0's just on the
basis of the strong coupling observed between the bulge and disk
scale-lengths in these galaxies.
Figure 1 is available in electronic form at http://www.aanda.org
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