  We performed K band surface photometry for luminous early-type galaxies in a
nearby rich cluster ABELL 2199. Combining it with B and R band surface
photometry, radial variations of B-R and R-K colours in the galaxies were
investigated. It is found that the inner regions of the galaxies are redder in
both of B-R and R-K colours. Comparing the radial variations of both of the
colours with predictions of Simple Stellar Population (SSP) models for a range
of ages and metallicities, it is suggested that the cluster ellipticals have
negative metallicity gradients but their age gradients are consistent with
zero, although our sample is small; the typical metallicity gradient is
estimated to be -0.16+- 0.09 in dlogZ/dlogr, while the age gradient is
estimated to be -0.10 +- 0.14 in dlog(age)/dlogr. Considering that similar
results have also been derived in the other recent studies using samples of
ellipticals in the Coma cluster and less dense environments, it seems that
there is no strong dependence on galaxy environment in radial gradient of
stellar population in elliptical galaxy.
