Observational insights on the formation scenarios of giant low surface brightness galaxies

TL;DR

This study investigates the formation of giant low surface brightness galaxies, suggesting they likely form through major mergers, supported by spectral and photometric data analysis of seven such galaxies.

Contribution

It provides observational evidence linking gLSBGs and compact ellipticals, supporting the major merger formation scenario over other models.

Findings

Most gLSBGs follow the Tully-Fisher relation.

Compact ellipticals are found as satellites in some gLSBGs.

Major mergers are a plausible formation pathway for gLSBGs.

Abstract

Giant low surface brightness galaxies (gLSBGs) with the disk radii of up to 130 kpc represent a challenge for currently accepted theories of galaxy formation and evolution, because it is difficult to build-up such large dynamically cold systems via mergers preserving extended disks. We summarize the in-depth study of the sample of 7 gLSBGs based on the results of the performed spectral long-slit observations at the Russian 6-m BTA telescope of SAO RAS, surface photometry and HI data available in literature. Our study revealed that most gLSBGs do not deviate from the Tully-Fisher relation. We discovered compact elliptical (cE) satellites in 2 out of these 7 galaxies. Provided the low statistical frequencies of gLSBGs and cEs, the chance alignment is improbable, so it can indicate that gLSBGs and cE are evolutionary connected and gives evidence in favor of the major merger formation scenario. Other formation paths of gLSBGs are also discussed.