Magnitude and Rotation of Galaxies

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This research project examines the relationship between the brightness of the three different types of galaxies, and their rotational velocities. I gathered data on the apparent magnitude and distance of galaxies to compute their brightness and determined their rotational velocities from an additional source. This relationship was first established by work relating to the Tully Fisher relationship, which showed a relationship between brightness and rotational velocity for spiral (S) class galaxies only. However, for this project I will compare this relationship for all galaxy types. The methods used to determine these relationships are to use the data to create scatter plots, calculate lines of best fit, and then compare the slopes of these lines to deduce which type of galaxies this relationship is prevalent and strongest in. The results of my investigation were that all three of the galaxy types have a direct relationship between the variables, which indicates that this relationship is a galactic property. However, according to slopes, SB class galaxies have the most direct relationship between the two variables, with twice as strong of a relationship.