Using spectra taken with the AAOmega spectrograph , we measure the radial velocities of over 100 stars , many of which are intermediate age carbon stars , in the direction of the dwarf irregular galaxy NGC 6822 .
Kinematic analysis suggests that the carbon stars in the sample are associated with NGC 6822 , and estimates of its radial velocity and galactic rotation are made from a star-by-star analysis of its carbon star population .
We calculate a heliocentric radial velocity for NGC 6822 of -51 \pm 3 km s ^ { -1 } and show that the population rotates with a mean rotation speed of 11.2 \pm 2.1 km s ^ { -1 } at a mean distance of 1.1 kpc from the galactic centre , about a rotation axis with a position angle of 26 ^ { \circ } \pm 13 ^ { \circ } , as projected on the sky .
This is close to the rotation axis of the HI gas disk and suggests that NGC 6822 is not a polar ring galaxy , but is dynamically closer to a late type galaxy .
However , the rotation axis is not aligned with the minor axis of the AGB isodensity profiles and this remains a mystery .