Personal webpage of Dr. Gunther Witzel

Research Highlights

Variability studies of Sagittarius A* provide direct information on the physics at spatial scales of the event horizon of the supermassive black hole at the center of the Milky Way. Learn about a long term study of  the properties of this variability and some extraordinary events in 2019 here
I presented a research talk (part 1 and part 2) on Sagittarius A* at the IAA in Granda, Spain, in November 2018.

The mysterious object G1 and G2 have been discovered in 2012 and are the only resolved instances of objects that tidally interact with a supermassive black hole. Despite predictions that G2 would be desinigrated during its periapsis passage in 2014, G2 survived. This implies a massive stellar core hidden at the center of the extended gas and dust envelope. Learn more.
I gave a research talk on G1 and G2 at the TDE Workshop in Jerusalem, Israel, in November 2015.

The instrumental polarization calibration for adaptive opitcs supported Nasmyth focus intruments is a challenge. We successfully calibrated the instrumental polarization of NAOS/CONICA at the VLT. A summary of our findings can be found in the ESO Messenger Vol. 142.