Stellar population gradients in bulges along the Hubble sequence ^*,**

I. The data

¹ Dpto. de Astrofísica, Facultad de Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
² Observatoire de l'Université de Genève, Laboratoire d'Astrophysique de l'École Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauverny, Switzerland e-mail: pascale.jablonka@obs.unige.ch
³ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

Received: 3 November 2006
Accepted: 28 June 2007

Abstract

This is the first paper presenting our long-term project aimed at studying the nature of bulges through analyzing their stellar population gradients. We present deep spectroscopic observations along the minor axis and the data reduction for a sample of 32 bulges of edge-on spiral galaxies. We explain in detail our procedures for measuring their dynamical parameters (rotation curves and velocity dispersion profiles) and line-strength indices, including the conversion to the Lick/IDS system. Tables giving the values of the dynamical parameters and line-strength indices at each galactocentric radius are presented (in electronic form) for each galaxy of the sample. The derived line-strength gradients from this dataset will be analyzed in a forthcoming paper to set constraints on the different scenarios for the formation of the bulges.