The dynamics of the giant dumbell galaxy IC 2082

Spectra have been obtained out to 35 arcsec on either side of the centre of the giant dumbell galaxy IC 2082 using the Image Photon Counting System of the Anglo-Australian Telescope. The galaxy has a binary component located 12 arcsec from the main nucleus and an elongated ($$\approx\text E_3-\text E_4$$) envelope. Our results show that (a) the stellar velocity dispersion increases with increasing radius indicating a rise in the mass-to-light ratio, (b) the central velocity dispersion is lower than would be expected given the galaxy's absolute magnitude, (c) the binary component has a relative velocity of $$\approx 240 \enspace\text {km s}^{-1}$$ compared to the main nucleus, (d) there is no detectable rotation in the envelope, and (e) absorption line measurements indicate a uniform metal abundance across the galaxy. These results are similar to those found by Dressier in his study of the cD galaxy in Abell 2029.