Spectra of 34 H II regions in the late-type galaxies NGC1087, NGC2967,
NGC3023, NGC4030, NGC4123, and NGC4517A were observed with the South African
Large Telescope (SALT). In all 34 H II regions, oxygen abundances were
determined through the "counterpart" method (C method). Additionally, in two H
II regions in which the auroral lines were detected oxygen abundances were
measured through the classic Te method. We also estimated the abundances in our
H II regions using the O3N2 and N2 calibrations and compared those with the
C-based abundances. With these data we examined the radial abundance
distributions in the disks of our target galaxies. We derived
surface-brightness profiles and other characteristics of the disks (the surface
brightness at the disk center and the disk scale length) in three photometric
bands for each galaxy using publicly available photometric imaging data. The
radial distributions of the oxygen abundances predicted by the relation between
abundance and disk surface brightness in the W1 band obtained for spiral
galaxies in our previous study are close to the radial distributions of the
oxygen abundances determined from the analysis of the emission line spectra for
four galaxies where this relation is applicable. Hence, when the
surface-brightness profile of a late-type galaxy is known, this parametric
relation can be used to estimate the likely present-day oxygen abundance in its
disk.Comment: 15 pages, 11 figures; Accepted for publication in Astronomy &
Astrophysic
