The Nature of Galactic Bulges from SAURON Absorption Line Strength Maps
Abstract
We discuss SAURON absorption line strength maps of a sample of 24 early-type spirals, mostly Sa. From the Lick indices H, 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.
Keywords
Cite
@article{arxiv.astro-ph/0702256,
title = {The Nature of Galactic Bulges from SAURON Absorption Line Strength Maps},
author = {Reynier F. Peletier and Jesus Falcon-Barroso and Katia Ganda and Roland Bacon and Michele Cappellari and Roger L. Davies and P. Tim de Zeeuw and Eric Emsellem and Davor Krajnovic and Harald Kuntschner and Richard M. McDermid and Marc Sarzi and Glenn van de Ven},
journal= {arXiv preprint arXiv:astro-ph/0702256},
year = {2009}
}
Comments
4 pages, 2 figures, to be published in the proceedings of IAU Symposium No. 241, "Stellar Populations as Building Blocks of Galaxies", editors A. Vazdekis and R.F. Peletier