EAS Publications Series
Volume 45, 2010GAIA: At the Frontiers of Astrometry
|Page(s)||421 - 424|
|Published online||15 February 2011|
C. Turon, F. Meynadier and F. Arenou (eds)
EAS Publications Series, 45 (2010) 421-424
Can thick disks originate through minor mergers?
GÉPI, Observatoire de Paris, CNRS, Université Paris Diderot,
5 place Jules Janssen, 92190 Meudon, France
In this study we use numerical N-body/SPH simulations to investigate the vertical stellar distribution of thick disks formed in minor mergers. These disks have a sech-shape vertical surface density profile which needs two sech functions with different scale heights to fit due to an additional stellar excesses at large heights (z ≳ 4 − 5 kpc). The scale heights of merger-induced thick disks increase with radius but the details of this thickening are sensitive to orbital configurations and gas fraction of the galaxies. The scale height of the stellar excess is constant with radius and largely independent of the initial conditions. The effects of minor mergers is cumulative in the sense that several minor mergers have the same impact of a single minor merger of the same total mass. Scattering by self-gravitating masses (clumps) in unstable gaseous disks can produce thick disks with constant scale height, however, there is not a stellar excess at large scale heights. Most of these results are found to be in good agreement with observations and thus we conclude that minor mergers remains a viable mechanism for the creation of galactic thick disks.
© EAS, EDP Sciences 2011