The Nature of Galactic Bulges from SAURON Absorption Line Strength Maps

Peletier, Reynier F.; Falcón-Barroso, Jesús; Ganda, Katia; Bacon, Roland; Cappellari, Michele; Davies, Roger L.; de Zeeuw, P. Tim; Emsellem, Eric; Krajnović, Davor; Kuntschner, Harald; McDermid, Richard M.; Sarzi, Marc; van de Ven, Glenn
Bibliographical reference

Stellar Populations as Building Blocks of Galaxies, Proceedings of IAU Symposium #241. Edited by A. Vazdekis and R. F. Peletier. Cambridge: Cambridge University Press, 2007, pp.485-488

Advertised on:
8
2007
Number of authors
13
IAC number of authors
0
Citations
4
Refereed citations
2
Description
We discuss SAURON absorption line strength maps of a sample of 24 early-type spirals, mostly Sa. From the Lick indices H$eta$, Mg b and Fe 5015 we derive SSP-ages and metallicities. By comparing the scaling relations of Mg b and H beta and central velocity dispersion with the same relation for the edge-on sample of Falcon-Barroso et al. (2002) we derive a picture in which the central regions of Sa galaxies contain at least 2 components: one (or more) thin, disc-like component, often containing recent star formation, and another, elliptical-like component, consisting of old stars and rotating more slowly, dominating the light above the plane. If one defines a bulge to be the component responsible for the light in excess of the outer exponential disc, then many Sa-bulges are dominated by a thin, disc-like component containing recent star formation.