2002AJ....124.2739F

We present deep, high angular resolution, near-infrared images of the obscured Galactic giant H II region NGC 3576. Our images reach objects to ∼3 M_☉. We collected high signal-to-noise K-band spectra of eight of the brightest objects, some of which are affected by excess emission and some of which follow a normal interstellar reddening law. None of them displayed photospheric features typical of massive OB-type stars. This indicates that they are still enshrouded in their natal cocoons. The K-band brightest source (NGC 3576 No. 48) shows CO 2.3 µm band head emission, and three others have the same CO feature in absorption. Three sources display spatially unresolved H₂emission, suggesting dense shocked regions close to the stars. We conclude that the remarkable object NGC 3576 No. 48 is an early B/late O star surrounded by a thick circumstellar disk/envelope. A number of other relatively bright cluster members also display excess emission in the K-band, indicative of reprocessing disks around massive stars (YSOs). Such emission appears to be common in other Galactic giant H II regions we have surveyed. The initial mass function slope of the cluster, Γ=-1.62, is consistent with Salpeter's distribution and similar to what has been observed in the Magellanic Cloud clusters and in the periphery of our Galaxy.