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