A slow bar in the dwarf irregular galaxy NGC 3741

Abstract

Using the Tremaine-Weinberg method, we measure the speed of the H I bar seen in the disc of NGC 3741. NGC 3741 is an extremely gas-rich galaxy with an HI disc which extends to about 8.3 times its Holmberg radius. It is also highly dark matter dominated. Our calculated value of the pattern speed ωp is 17.1 ± 3.4 kms-1 kpc-1.We also find the ratio of the corotation radius to the bar semimajor axis to be (1.6 ± 0.3), indicating a slow bar. This is consistent with bar models in which dynamical friction results in a slow bar in dark-matter-dominated galaxies. ©2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.