HI observations of nearby galaxies V. Narrow (HI) line galaxies

Abstract

In this paper we present new HI observations with high velocity resolution for 104 nearby narrow-line galaxies with half power line widths smaller than 50 km s-1 most of which are well approximated by a Gaussian. The FWHM line width of 30 of these integrated HI profiles is less than 25 km s-1. We present global parameters of these nearby galaxies and discuss the size dependence, the luminosity dependence, and the dependence of these parameters with the observed line width. Our sample essentially is a subsample of the Local Volume (i.e. galaxies within 10 Mpc) with declinations >-30° and only a few galaxies at greater distances. It is described by the following median values of global physical parameters: total absolute blue magnitude MBt = -12.85; linear diameter A0 = 1.63 kpc (this corresponds to the de Vaucouleurs diameter D25); half power line width Wc = 29 kms-1; total HI mass MHI = 2 × 107 M⊙; distance D = 5.1 Mpc; III mass-to-luminosity ratio MHI/LB = 0.9 M⊙/L⊙; total mass-to luminosity ratio Mt/LB = 2.9 M⊙/L⊙.