Orateur
Gernot Heißel
(Observatoire de Paris / LESIA)
Description
The continuous monitoring of stellar orbits in the Galactic Centre over the past few decades revealed the massive central object Sgr A at their shared focal point (→ Nobel prize 2020). These and other observations (orbits of hot flares, black hole shadow) are in best agreement with the notion of Sgr A being a massive black hole of about 4 million solar masses. Assuming the black hole model, the orbit of the star S2 (also S-02) also allowed for the observation of relativistic effects (gravitational redshift, Schwarzschild precession).
While we currently do not see any matter between the innermost known S-stars (e.g. S2) and the accretion flow of Sgr A*, observations still allow for the presence of at least a few thousand solar masses of distributed matter, such as a cluster of faint stars and stellar remnants,(particle) Dark Matter or a combination thereof. Depending on the nature of the distributed matter, theory predicts it to attain certain density profiles.
In my talk I will first summarise some recent theoretical results as well as observational upper bounds on dark mass distributions around Sgr A*. I will then introduce a novel mass shell model for such matter distributions, which does not assume a specific functional form of the density profile a priori, but rather obtains this form from fitting it to the data. For this I will present a proof of concept.
Author
Gernot Heißel
(Observatoire de Paris / LESIA)
