We present a study of globular clusters in the inner region of the giant elliptical galaxy NGC 4472 , based on the HST WFPC2 archive data .
We have found about 1560 globular cluster candidates at the galactocentric radius r < 4 arcmin , most of which are located within r = 1.1 arcmin . V - ( V - I ) diagram of these objects shows a dominant vertical structure which consists obviously of two components : blue globular clusters ( BGCs ) and red globular clusters ( RGCs ) .
The luminosity function of the globular clusters is derived to have a peak at V ( max ) = 23.50 \pm 0.16 mag and \sigma = 1.19 \pm 0.09 from Gaussian fitting .
From this result the distance to NGC 4472 is estimated to be d = 14.7 \pm 1.3 Mpc , for the foreground reddening E ( V - I ) = 0.03 and the peak luminosity for the Galactic globular clusters of M _ { V } ( max ) = -7.4 mag .
The peak luminosity for the RGCs is similar to that for the BGCs , which indicates that the RGCs may be several Gyrs younger than the BGCs .
The luminosity function of the globular clusters shows little systematic variation depending on the galactocentric radius at r < 4 arcmin .
However , the mean luminosity of the bright BGCs decreases by 0.2 mag with increasing galactocentric radius over the range of 9 arcmin , while that of the RGCs does not .
The observed color distribution of these globular clusters is distinctively bimodal with peaks at ( V - I ) = 0.98 \pm 0.01 and 1.23 \pm 0.01 , which correspond to the metallicities of [ Fe/H ] = -1.41 and -0.23 dex , respectively .
The mean observed color of all the globular clusters with V < 23.9 mag is derived to be ( V - I ) = 1.11 \pm 0.01 ( m.e .
) , corresponding to the metallicity of [ Fe/H ] = -0.79 \pm 0.05 dex .
These colors are exactly the same as those for the globular clusters in M87 .
It is found that the relative number of the BGCs to the RGCs is increasing with the increasing galactocentric radius .
There are more RGCs than the BGCs within r \sim 2 arcmin , while there are fewer RGCs than the BGCs in the outer region of NGC 4472 .
Radial and azimuthal structures of the globular cluster system in NGC 4472 are also investigated .
Surface number density profiles of both the BGCs and RGCs get flat in the central region , and the core radii of the globular cluster systems are measured to be r _ { c } = 1.9 arcmin for the BGCs , r _ { c } = 1.2 arcmin for the RGCs , and r _ { c } = 1.3 arcmin for the total sample , which are much larger than the stellar core of the galaxy .
In general the properties of the globular clusters in the inner region of NGC 4472 are consistent with those of the globular clusters in the outer region of NGC 4472 .