Bonn 2010 – scientific programme

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SYBH: Symposium Black Holes

SYBH 1: Symposium Black Holes (SYBH)

SYBH 1.4: Invited Talk

Monday, March 15, 2010, 15:20–15:55, HG Aula

Super-Massive Black Holes at the Centers of Galaxies: The Case of Sagittarius A* at the Center of the Milky Way — •Andreas Eckart — I.Physikalisches Institut ; Zülpicher Str. 77; 50937 Koeln

The dynamics of stars and gas at the centers of galaxies show that in almost all cases they harbor super-massive black holes (SMBH) with masses between a few million and one-hundred million solar masses. The closest of these objects is Sagittarius~A* (Sgr~A*), the radio to X-ray source associated with the super-massive 4 million solar mass black hole at the center of the Milky Way. Here the central mass can undoubtedly be determined from a stellar orbits. In addition, violent flare emission allows us to probe the immediate environment of the central mass. Near-infrared polarimetry shows signatures of strong gravity that are statistically significant against randomly polarized red noise allowing to derive spin and inclination information of the SgrA* SMBH. A combined synchrotron self Compton (SSC) and adiabatic expansion model with source component spectra peaking at a few THz can fully account for the observed flare flux densities and delay times covering the spectral range from the X-ray to the mm-radio domain. The light curves of SgrA* suggest that the mm-wavelength flare emission follows the optically thin THz to near-infrared emission with a delay of 1.5 - 2 hours. Two cometary shaped stellar sources in the vicinity of SgrA* as well as the proper motions of thin dusty filaments in the mini-spiral may represent one of the best indicators for a >1000 km/s fast wind emerging from the center.