Revealing a clustered region of massive star formation through NIR jets using VLT instruments

Massive stars play crucial roles in determining the physical and chemical evolution of galaxies. They shape their environment from early in their protostellar phase when they blast the surrounding with powerful jets, up until their violent deaths in the form of supernova. However, they form deeply embedded in their parental clouds, making it challenging to directly observe these stars and immediate environments. Notwithstanding, their massive outflows can extend several parsecs and since accretion and ejection processes are intrinsically related, they can provide crucial information about the processes governing massive star formation. In this talk, I will present the IRAS 18264-1152 high-mass star-forming complex and reveal the jets through NIR spectro-imaging. We observe the molecular hydrogen (H2) NIR jets in the K-band (1.9-2.5µm) obtained with the integral field units VLT/SINFONI and VLT/KMOS. We compare the geometry of the NIR outflows with that of the associated molecular outflow, probed by CO(2-1) emission mapped with the SMA. The spectro-imaging analysis focuses on the H2 jets, for which we derived visual extinction, temperature, column density, area, and mass. The intensity, velocity, and excitation maps based on H2 emission strongly support the existence of a protostellar cluster in this region, with at least two (but up to four) different large-scale outflows, found through the NIR and radio observations. This multi-wavelength comparison also allows us to derive a stellar density of 4000 stars pc-3 showing that relatively low number density region can harbour massive protostars. In conclusion, our study reveals the presence of several outflows driven by young sources from a forming cluster of young massive stars. Moreover, the derived stellar number density together with the geometry of the outflows suggest that massive stars can form in a relatively ordered manner in this cluster.