Merging or division. I. Dependencies between the magnitude gap of groups and the morphology of two brightest galaxies

TL;DR

This study investigates how the morphological types of the brightest galaxies in groups relate to the magnitude gap, finding no increase in ellipticals with larger gaps, challenging the merger hypothesis.

Contribution

It provides new evidence that the morphological types of top galaxies are not dependent on the magnitude gap, contradicting previous merger-based theories.

Findings

No increase in elliptical galaxies with larger magnitude gaps

Results contradict the merger hypothesis

Supports Ambartsumian's alternative hypothesis

Abstract

In the present study, the dependences of the morphological types of the first and second ranked group galaxies on the magnitude gap were studied. It is shown that there is no increase in the relative number of elliptical galaxies among the first and second ranked group galaxies with a large magnitude gaps (in comparison with the expected, assuming that the morphological type of these galaxies does not depend on the magnitude gap). This result contradicts the merger hypothesis. The hypothesis proposed by Ambartsumian does not contradict this result.