Young Stars at the Center of the Milky Way?

Abstract

We present results from the first diffraction-limited images of the Galactic center (GC) at 1.6, 2.1, and 3.8 ÄÄmu;m with the new adaptive optics (AO) camera NAOS/CONICA at the ESO Very Large Telescope, as well as 3-4 ÄÄmu;m low-resolution spectroscopy. We have discovered a small (0.13 lt-yr diameter) cluster of compact sources about 0.5" north of IRS 13 with strong IR excesses due to TÄÄgt;500 K dust. The nature of the sources is unclear. They may be a cluster of highly extincted stars that heat the local environment of the minispiral. We also consider an explanation that involves the presence of young stars at evolutionary stages between young stellar objects and Herbig Ae/Be objects with ages of about 0.1 to 1 million yr. This scenario would imply more recent star formation in the GC than previously suspected. The AO observations also resolve the central IRS 13 complex. In addition to the previously known bright stars E1 and E2, the K- and L ' -band images for the first time resolve object E3 into two components, E3N and E3c. The latter one is closest to the 7 mm Very Large Array radio continuum source found at the location of the IRS 13 complex. E3c may be associated with a strong stellar wind or a dusty Wolf-Rayet-like star at that location.