The AGB population in IC 1613 using JHK photometry
  A member of the Local Group, IC 1613 is a gas rich irregular dwarf galaxy
that appears to have formed stars continuously over the last 10 Gyr and is
relatively independent of external influences from other galaxies. This paper
aims to study the spatial distribution of the asymptotic giant branch (AGB)
population in IC 1613 and its metallicity. Using WFCAM on UKIRT, high quality
JHK photometry of an area of 0.8 deg^2 centered on IC 1613 was obtained. The
data have been used to isolate the C- and M-type components of the AGB
population and using their number ratio, C/M, a global mean metallicity has
been derived. The metallicity and the TRGB magnitude have been studied as a
function of distance from the galactic centre and as a function of azimuthal
angle. The tip of the RGB (TRGB) has been found at K_0 = 18.25 +/- 0.15 mag.
The colour separation between the C- and M-type components of the AGB
population has been located at (J-K) = 1.15 +/- 0.05 mag, giving a global C/M
ratio of 0.52 +/- 0.04 and from this an iron abundance of [Fe/H] = -1.26 +/-
0.07 dex has been calculated. The AGB population has been detected out to a
radial distance of 4.5 kpc in the de-projected plane of the galaxy. The
measured TRGB is consistent with previous measurements and no significant
variation is detected in the TRGB or in metallicity either with galactocentric
distance or azimuthal angle.
