The Local Group Galaxy NGC 6822 and its Asymptotic Giant Branch Stars
  JHKs photometry is presented from a 3.5 year survey of the central regions of
the irregular galaxy NGC6822. The morphology of the colour-magnitude and
colour-colour diagrams is discussed with particular reference to M, S and
C-type AGB stars and to M-supergiants. Mean JHKs magnitudes and periods are
given for 11 O-rich and 50 presumed C-rich Miras. Data are also listed for 27
large amplitude AGB stars without periods and for 69 small amplitude AGB
variables. The slope of the bolometric period-luminosity relation for the
C-rich Miras is in good agreement with that in the LMC. Distance moduli derived
from the C- and O-rich Miras are in agreement with other estimates. The period
distribution of C-rich Miras in NGC6822 is similar to that in the Magellanic
Clouds, but differs from that in the dwarf spheroidals in the Local Group. In
the latter there is a significant proportion of large amplitude, short period
variables indicating a population producing old carbon-rich AGB stars.
