Galactic bulges: the importance of early formation scenarios vs. secular evolution

Seidel, M. K.; Cacho, R.; Ruiz-Lara, T.; Falcón-Barroso, J.; Pérez, I.; Sánchez-Blázquez, P.; Vogt, F. P. A.; Ness, M.; Freeman, K.; Aniyan, S.
Bibliographical reference

Galaxies in 3D across the Universe, Proceedings of the International Astronomical Union, IAU Symposium, Volume 309, pp. 163-164

Advertised on:
2
2015
Number of authors
10
IAC number of authors
2
Citations
0
Refereed citations
0
Description
We study the stellar content of three galactic bulges with the high resolution gratings (R=7000) of the WiFeS integral field unit in order to better understand their formation and evolution. In all cases we find that at least 50% of the stellar mass already existed 12 Gyrs ago, more than currently predicted by simulations. A younger component (age between ~1 to ~8 Gyrs) is also prominent and its present day distribution seems to be much more affected by morphological structures, especially bars, than the older one. This in-depth analysis supports the notion of increasing complexity in bulges which cannot be achieved by mergers alone, but requires a non-negligible contribution from secular evolution.