Surface photometry of spiral galaxies in NIR: Structural parameters of disks and bulges

Abstract

A sample of 40 bright spiral galaxies (BT < 12) with low inclination and without bar was observed with JHK lters. For this purpose the MAGIC NICMOS3 camera at the 2.2 m telescope of the Calar Alto observatory, Spain was used. With a newly developed 2-dimensional algorithm the distribution of the surface brightness was tted simultaneously by corresponding functions for the disk- and bulge-structure. While the disk was tted with an exponential function, the bulge prole was tted with a generalized de Vaucouleurs R law, with the concentration parameter =1 =n as a further t variable. The correlation of the resulting structural parameters of disks and bulges lead to some interesting relations: 1. The use of a variable exponent is necessary for a realistic description of the bulge structure; 2. Disks and bulges show similar correlations between eective radius, eective surface brightness and luminosity; 3. They populate a common strip in the fundamental plane; 4. From the correlations between and Hubble type some conclusions about the formation and evolution of spiral galaxies can be drawn.