The Young Stars in the Galactic Center
In this paper I've compiled the largest ever spectroscopic survey of the Galactic Center using SINFONI instrument at the VLT. The observations have been taken over a period of 20 years, some even by myself. We use these observations to measure the spectra of over 2800 stars. Among them, 200 which formed just 6 million years ago (give or take a couple of million years)! The spectra than allow us to determine the velocities of each star, and with that we can deduce that they co-rotate and life in several disks and filaments. Several disks had been proposed in the past, which we confirm, and also find a new one!
Left: All young stars in the Galactic Center for which we do not know the orbit.
We can still learn something about these stars by employing statistical tricks, which allow us to tell if the stars share similar orbits.
​
Below: Using the aforementioned tricks we can determine that many of the stars share angular momentum. They live in disks or filaments!
Scientific Abstract
We present a large ∼30'' × 30'' spectroscopic survey of the Galactic Center using the SINFONI IFU at the VLT. Combining observations of the last two decades we compile spectra of over 2800 stars. Using the Bracket-γ absorption lines, we identify 195 young stars, extending the list of known young stars by 79. In order to explore the angular momentum distribution of the young stars, we introduce an isotropic cluster prior. This prior reproduces an isotropic cluster in a mathematically exact way, which we test through numerical simulations. We calculate the posterior angular momentum space as a function of projected separation from Sgr A*. We find that the observed young star distribution is substantially different from an isotropic cluster. We identify the previously reported feature of the clockwise disk and find that its angular momentum changes as a function of separation from the black hole and thus confirm a warp of the clockwise disk (p ∼ 99.2%). At large separations, we discover three prominent overdensities of the angular momentum. One overdensity has been reported previously, the counterclockwise disk. The other two are new. Determining the likely members of these structures, we find that as many as 75% of stars can be associated with one of these features. Stars belonging to the warped clockwise disk show a top-heavy K-band luminosity function, while stars belonging to the larger separation features do not. Our observations are in good agreement with the predictions of simulations of in situ star formation and argue for the common formation of these structures.