One of the largest rotation curve (RC) databases of spiral galaxies currently available is provided by the kinematic and photometric data of Stephane Courteau. These RCs were originally obtained for cosmic flow studies. The final collection of RCs consists of 304 galaxies. This collection includes 64 RCs of morphological type Sb galaxies which are the subject of the present analysis. In the context of our study of these 64 northern spirals, we show that the velocity of the test particle in galactic region can be described by generalized power law. It is found that RCs impose an extremely strong correlation between the free parameters of the power law, and this correlation accounts for virtually all the variation in the pivotal diagram. The analysis brings out clearly that RCs can be partitioned into well-defined discrete subclasses. Our analysis of data yields results similar to those obtained by D F Roscoe for southern sky galaxies. This clearly indicates that galaxies can be classified into discrete subclasses according to their dynamics in context of power law.

The present work is motivated by an extensive analysis of southern sky spiral galaxies performed by Roscoe (1999). The following study performs the same analysis of northern sky spiral galaxies and confirms the power-law structure.
where V and R are rotational velocity and radial position of a test particle in galactic region with respect to center of the galaxy. There are two free parameters; one is proportionality constant A and the other is a which describes the nature of the power law. From the point of view of reconciling the hypothesis with the observations, a is constrained to be ³ –1. Application of power law to analyze the RCs involves correlations imposed on free parameters (A, a). The perfect correlation is not expected as the RC data is noisy; still a better correlation is always searched for.

Science and Technology Journal, Seismic Evaluation of Flat Slab Buildings, Flat Slab System, Finite Element Method, Wide Column Model, Design parameters, Static Linear Analysis, Equivalent Frame Method, Nonlinear Analysis, Flat Slab Structures, Equivalent Frame Method.