The age of the inner halo globular cluster NGC 6652

Hubble Space Telescope (V, I) photometry has been obtained for the inner halo globular cluster NGC 6652. The photometry reaches similar to4 mag below the turnoff and includes a well-populated horizontal branch. This cluster is located close to the Galactic center, at R-GC similar or equal to 2.0 kpc, with a reddening of E(V-I)= 0.15 +/- 0.02, and has a metallicity of [Fe/H] similar or equal to -0.85. Based upon DeltaV(HB)(SGB), NGC 6652 is 11.7 +/- 1.6 Gyr old. Using DeltaV(HB)(SGB),B, precise differential ages for 47 Tuc (a thick disk globular cluster), M107,and NGC 1851 (both halo clusters) were obtained. NGC 6652 appears to be the same age as 47 Tuc and NGC 1851 (within +/-1.2 Gyr), while there is a slight suggestion that M107 is older than NGC 6652 by 2.3 +/- 1.5 Gyr. As this is a less than 2 sigma result, this issue needs to be investigated further before a definitive statement regarding the relative age of M107 and NGC 6652 may be made.