2007A&A...465..931N

Recent observational results suggest that high-mass (proto-)stars form in a similar way to low- and intermediate-mass stars, i.e., via disk accretion of gas and dust. To further characterize and understand the on-going physical processes associated with a large circumstellar disk, seen as a dark silhouette against the bright background of the M17 Hii region, we report and discuss new high angular resolution integral field spectroscopy performed in the K-band. The data were taken with the Adaptive Optics (AO) supported near-infrared integral field spectrograph SINFONI at ESO's Very Large Telescope Yepun (VLT UT4) as part of the science verification of this new instrument. Based on obtained H₂ v=1-0S(1) and H₂ v=1-0S(3) emission maps, we report the discovery of a H₂ jet, which apparently arises from the suspected protostellar source(s) located at the very center of the disk. In addition, both diameter (about 4000AU) and sub-structures of the innermost, densest part of the flared disk are infered from Brγ, Brδ, and HeI maps. Because ejection of material through a jet/outflow is always linked to accretion of gas and dust either onto the circumstellar disk or onto the central (protostellar) source(s), the presence of a collimated H₂ jet provides indirect but unquestionable evidence for ongoing accretion processes in the case of the M 17 disk. The high mass outflow and accretion rates of >10^–5M_☉/yr derived from the SINFONI data suggest that a star of rather high mass is forming.