Evidence for Warped Disks of Young Stars in the Galactic Center

Abstract

The central parsec around the super-massive black hole in the Galactic Center hosts more than 100 young and massive stars. Outside the central cusp (R ∼ 1 ′ ′ ) the majority of these O and Wolf-Rayet (WR) stars reside in one or two disks. Here we present the results from new observations of the Galactic Center with the AO-assisted near-infrared imager NACO and the integral field spectrograph SINFONI on the ESO/VLT. These include the detection of 27 new reliably measured WR/O stars in the central 12 ” and improved measurements of 63 previously detected stars, with proper motion uncertainties reduced by a factor of four compared to our earlier work. Based on the sample of 90 well measured WR/O stars, we develop a detailed statistical analysis of their orbital properties and orientations. We show that half of the WR/O stars are compatible with being members of a clockwise rotating system. The rotation axis of this system shows a strong transition from the inner to the outer regions as a function of the projected distance from Sgr A*. The clockwise system is compatible with a warped disk with a local two-dimensional Gaussian thickness of about a