Constraints on the angular distribution of satellite galaxies about spiral hosts

TL;DR

This study introduces a new method to analyze the angular distribution of satellite galaxies around isolated spiral hosts, finding that their distribution is nearly isotropic, which informs models of galaxy formation.

Contribution

The paper presents a novel technique using systematic binning and maximum likelihood analysis to constrain satellite galaxy distributions around spiral hosts.

Findings

Satellite distributions are nearly isotropic.

Method allows for exclusion of highly anisotropic models.

Technique can be refined for future surveys.

Abstract

We present, using a novel technique, a study of the angular distribution of satellite galaxies around a sample of isolated, blue host galaxies selected from the sixth data release of the Sloan Digital Sky Survey. As a complement to previous studies we subdivide the sample of galaxies into bins of differing inclination and use the systematic differences that would exist between the different bins as the basis for our approach. We parameterize the cumulative distribution function of satellite galaxies and apply a maximum likelihood, Monte-Carlo technique to determine allowable distributions, which we show as an exclusion plot. We find that the allowed distributions of the satellites of spiral hosts are very nearly isotropic. We outline our formalism and our analysis and discuss how this technique may be refined for future studies and future surveys.