Mid-IR Probes of the ISM and Stellar Populations at the Galactic Center
Nous présentons nos dernières observations du centre Galactique dans le proche infrarouge et dans l'infrarouge moyen à l'aide des instruments de dernière génération de l'ESO.
We present the results of our last nearand mid-IR (NIR and MIR) observations of the central parsec of our Galaxy. These investigations benefit from the high quality of the ESO instrumentation. Spectroscopic observations with ISAAC at the ESO VLT enabled us to build the first L-band data-cube of the central region corrected for the foreground extinction. This led to the discovery of 3 Wolf-Rayet stars all of which show, for the first time, prominent HeII emission lines in their MIR spectra providing an indication of their early evolutionary phase. The datacube also enabled us to study the distribution of water ice and hydrocarbon absorption features in the central parsec. Also, recent ISAAC M-band spectroscopic observations of a number of bright sources in the central parsec are presented and the preliminary study of the CO gasand solid-phase distributions are discussed. NACO NIR photometry combined with VISIR Nand Q-band MIR photometry enabled us to construct Spectral Energy Distributions of over 60 compact sources. We identified four typical classes of sources, each of which show characteristic features that may enable us to understand the nature of previously unclassified objects in the region. Moreover, we performed the first interferometric investigations of individual sources at the Galactic Center with MIDI at the VLTI and we resolved for the first time the dust shell of the bright source IRS 3. Finally, the most important results of NIR NACO observations, allowed us to investigate the structure of the central stellar cluster, are also presented.
Jihane MOULTAKA, Thomas VIEHMANN, Rainer SCHÖDEL, Jorg-Uwe POTT, Andreas ECKART
centre galactique, milieu interstellaire, populations stellaires.
galactic center, interstellar medium, stellar populations.