Dark matter in the inner parts of barred galaxies: The data

¹ Kapteyn Astronomical Institute, University of Groningen, Postbus 800, Groningen 9700 AV, The Netherlands e-mail: isa@astro.rug.nl
² RSAA, Mount Stromlo Observatory, Cotter road, Weston Creek, ACT 2611, Australia
³ Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, 18080 Granada, Spain
⁴ Geneva Observatory, Ch. des Maillettes 51, 1290 Sauverny, Switzerland

Received: 14 January 2005
Accepted: 11 April 2005

Abstract

This paper presents surface photometry and H_α rotation curves of 27 isolated spiral galaxies. The final goal is to obtain the mass distribution of a sample of isolated spiral galaxies in order to model their gas kinematics. This is then compared to the observed rotation curve, to determine the necessity of a dark halo in the inner parts (Perez et al. 2004, A&A, 424, 799). The azimuthally averaged radial surface brightness profiles and the integrated magnitudes obtained from ellipse fitting are given for each of the sample galaxies. The ellipse fitting technique applied to the light distribution also allowed us to obtain the size of the bar, and the inclination and position angle of the outer isophotes that allow the galaxy deprojection. Using these profiles, 1-D disk-bulge decomposition was performed to obtain the disk scale-length and the bulge effective radius for the different bands. Through the fitting of a parametric function to the observed rotation curve, the maximum rotational velocity and the corresponding radius was obtained. The correlation between the bulge and disk parameters is in agreement with previous studies (de Jong 1996a, A&A, 313, 45; Márquez & Moles 1999, A&A, 344, 421; Baggett et al. 1998, AJ, 116, 1626). Regarding the Kormendy relation (Kormendy 1977, ApJ, 218, 333), in agreement with de Jong, no correlation between the bulge effective radius and its surface brightness is found, possibly due to the small range of bulge magnitudes covered. We find a smaller scatter in the structural relations when compared to non-isolated samples in agreement with Márquez & Moles (1999). Finally, a correlation between the disk scale-length and the bar size is observed, possibly reflecting the rapid growth of a bar.