1999A&A...343L...9D

The VLT on Cerro Paranal was used to observe four fields located at ∼2.3' from the center of the Galactic globular cluster NGC6712 in the V and R bands. The resulting color-magnitude diagram shows a well defined main sequence reaching down to the 5σ detection limit at V≃25, R≃23.5 or approximately 4 magnitudes below the main sequence turn-off, the deepest obtained so far on this cluster. This yields a main sequence luminosity function that peaks at M_R≃4.5 and drops down to the 50% completeness limit at M_R≃8.5. Transformation to a mass function via the latest mass-luminosity relation appropriate to this object indicates that the peak of the luminosity function corresponds to ∼0.75M_☉, a value significantly higher than the ∼0.25M_☉, measured for most other clusters observed so far. Since this object, in its Galactic orbit, penetrates very deeply into the Galactic bulge with perigalactic distance of ∼0.3kpc, this result is the first strong evidence that tidal forces have stripped this cluster of a substantial portion of its lower mass star population all the way down to its half-light radius and possibly beyond.