Bibcode
Bekki, K.; Couch, W. J.; Shioya, Y.; Vazdekis, A.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 359, Issue 3, pp. 949-965.
Fecha de publicación:
5
2005
Número de citas
70
Número de citas referidas
66
Descripción
We investigate the structural, kinematical and spectrophotometric
properties of `E+A' galaxies - those with strong Balmer absorption lines
but no significant [OII] emission - using numerical simulations combined
with stellar population synthesis codes. We particularly focus on the
two-dimensional (2D) distributions of line-of-sight velocity, velocity
dispersion, colour and line index in E+A galaxies formed via the
interaction and merging of two gas-rich spirals. Our numerical
simulations demonstrate that E+A elliptical galaxies formed by major
galaxy merging have positive radial colour gradients and negative radial
Hδ gradients by virtue of their central post-starburst
populations. Furthermore, we show that the projected kinematical and
spectroscopic properties of the simulated E+A galaxies can be remarkably
different for different major merger models. For example, the simulated
E+A ellipticals with kinematically decoupled cores clearly show regions
of strong Hδ absorption which are very flattened, with differences
in rotation and velocity dispersion between the old and young stars. E+A
ellipticals are highly likely to show more rapid rotation and a smaller
central velocity dispersion in young stars than in old ones. E+A
galaxies formed from the strong tidal interaction between gas-rich
spirals have discy morphologies with thick discs and are highly likely
to be morphologically classified as barred S0 galaxies. We also provide
specific predictions on the structural, kinematical and
spectrophotometric properties of young globular cluster systems in E+A
galaxies. Based on these results, we discuss the importance of spatially
resolved, integral field unit spectroscopy on large (8-10 m)
ground-based telescopes in confirming the formation of kinematically
distinct cores in elliptical galaxies produced via dissipative merging
and determining the most probable physical mechanism(s) for E+A
formation with discy and spheroidal morphologies.