2006MNRAS.373..700B

We present an updated investigation of the relation between large-scale disc circular velocity, v_c, and bulge velocity dispersion, σ_c. New bulge velocity dispersions are measured for a sample of 11 low surface brightness (LSB) and seven high surface brightness (HSB) spiral galaxies for which v_cis known from published optical or Hi rotation curves. We find that, while LSB galaxies appear to define the upper envelope of the region occupied by HSB galaxies (having relatively larger v_cfor any given σ_c), the distinction between LSB and HSB galaxies in the v_c-σ_cplane becomes less pronounced for σ_c≲ 80 km/s. We conclude that either the scatter of the v_c-σ_crelation is a function of v_c(and hence galaxy mass) or the character of the v_c-σ_crelation changes at v_c∼ 80 km/s. Some implications of our findings are discussed.