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Abstract: We present new observations of the nuclear star cluster in the central parsecof the Galaxy with the adaptive optics assisted, integral field spectrographSINFONI on the ESO-VLT. Our work allows the spectroscopic detection of earlyand late type stars to m K >= 16, more than 2 magnitudes deeper than ourprevious data sets. Our observations result in a total sample of 177 bona fideearly-type stars. We find that most of these Wolf Rayet WR, O- and B- starsreside in two strongly warped disks between 0.8- and 12- from SgrA*, as well asa central compact concentration the S-star cluster centered on SgrA*. Thelater type B stars m K>15 in the radial interval between 0.8- and 12- seem tobe in a more isotropic distribution outside the disks. The observed dearth oflate type stars in the central few arcseconds is puzzling, even when allowingfor stellar collisions. The stellar mass function of the disk stars isextremely top heavy with a best fit power law of dN-dm ~ m^-0.45+-0.3. Sinceat least the WR-O-stars were formed in situ in a single star formation event ~6Myrs ago, this mass function probably reflects the initial mass function IMF.The mass functions of the S-stars inside 0.8- and of the early-type stars atdistances beyond 12- are compatible with a standard Salpeter-Kroupa IMF bestfit power law of dN-dm ~ m^-2.15+-0.3.



Author: H. Bartko, F. Martins, S. Trippe, T. K. Fritz, R. Genzel, T. Ott, F. Eisenhauer, S. Gillessen, T. Paumard, T. Alexander, K. Dodds

Source: https://arxiv.org/







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