Variability of Young Massive Stars in the Arches Cluster: Accurate   Photometry with Adaptive Optics
  We present preliminary results of the first near-infrared variability study of the Arches cluster, using adaptive optics data from NIRI/Gemini and NACO/VLT. The goal is to discover eclipsing binaries in this young (2.5 $\pm$ 0.5 Myr), dense, massive cluster for which we will determine accurate fundamental parameters with subsequent spectroscopy. Given that the Arches cluster contains more than 200 Wolf-Rayet and O-type stars, it provides a rare opportunity to determine parameters for some of the most massive stars in the Galaxy. 
K. Markakis, A.Z. Bonanos, G. Pietrzynski, L. Macri, K.Z. Stanek
astro-ph.SR