Using an Assumption about the Monotony of Spiral Arms to Determine the Orientation Angles of Galaxies

TL;DR

This paper introduces a new method for determining the orientation angles of spiral galaxies by assuming their spiral arms are monotonic functions, potentially offering more accurate results than traditional isophote methods.

Contribution

The paper proposes a novel approach based on spiral arm monotonicity to improve the accuracy of galaxy orientation angle measurements.

Findings

Method applied to 43 galaxies shows good agreement with existing data.

Potential for more accurate orientation measurements than traditional methods.

Demonstrates the effectiveness of the monotonicity assumption in galaxy analysis.

Abstract

A method is proposed for the determination of the position and inclination angles of the plane of a spiral galaxy based on the assumption that every spiral arm is a monotonic function of the radius versus azimuthal angle. This method may yield more accurate results than the more commonly employed isophote method, which is fraught with various drawbacks. The use of the new method is illustrated by applying it to a sample of 43 objects, and the results agree well with data from other sources.