Bibcode
González-García, A. C.; Balcells, M.; Olshevsky, V. S.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society: Letters, Volume 372, Issue 1, pp. L78-L82.
Advertised on:
10
2006
Citations
31
Refereed citations
29
Description
We analyse the skewness of the line-of-sight velocity distributions in
model elliptical galaxies built through collisionless galaxy mergers. We
build the models using large N-body simulations of mergers between
either two spiral or two elliptical galaxies. Our aim is to investigate
whether the observed ranges of skewness coefficient (h3) and
the rotational support (V/σ), as well as the anticorrelation
between h3 and V, may be reproduced through collisionless
mergers. Previous attempts using N-body simulations failed to reach
V/σ ~ 1-2 and corresponding high h3 values, which
suggested that gas dynamics and ensuing star formation might be needed
in order explain the skewness properties of ellipticals through mergers.
Here we show that high V/σ and high h3 are reproduced
in collisionless spiral-spiral mergers whenever a central bulge allows
the discs to retain some of their original angular momentum during the
merger. We also show that elliptical-elliptical mergers, unless merging
from a high-angular momentum orbit, reproduce the strong skewness
observed in non-rotating, giant, boxy ellipticals. The behaviour of the
h3 coefficient therefore associates rapidly-rotating discy
ellipticals to disc-disc mergers, and associates boxy, slowly rotating
giant ellipticals to elliptical-elliptical mergers, a framework
generally consistent with the expectations of hierarchical galaxy
formation.