The Stellar Disk Thickness of Low Surface Brightness Galaxies

Abstract

We present surface photometry results for a sample of 11 edge-on galaxies observed with the 6 m telescope at the Special Astrophysical Observatory, Russia. The photometric scale length, scale height, and central surface brightness of the stellar disks of our sample galaxies are estimated. We show that four galaxies in our sample, which are visually classified as objects of the lowest surface brightness class in the Revised Flat Galaxy Catalog, have bona fide low surface brightness (LSB) disks. We find from a comparison of photometric scales that the stellar disks of LSB galaxies are thinner than those of high surface brightness (HSB) galaxies. There is a clear correlation between the central surface brightness of the stellar disk and its vertical-to-radial scale ratio. The masses of spherical subsystems (dark halo + bulge) and the dark halo masses are obtained for the sample galaxies based on the thickness of their stellar disks. The LSB galaxies tend to harbor more massive spherical subsystems than the HSB objects, whereas no systematic difference in the dark halo masses is found between LSB and HSB galaxies. At the same time, the inferred mass-to-luminosity ratio for the LSB disks appears to be systematically higher than for HSB disks.