A New Potential Formula Applicable to Flattened Systems

Abstract

A new formula for the gravitational potential of flattened systems is proposed. It is a modification of the Miyamoto-Nagai potential and should be applied to very flattened systems, exponential discs as a typical example. The resulting rotation curve agrees sufficiently well with that obtained by using special functions and the total masses remain the same. The functions contained in the new term can improve the agreement for the rotation curve and also reduce the effect of negative density values which appear off the midplane.Comment: 5 pages, 4 figures, accepted for publication in PAS