Speaker
Description
Resolving the rich structure in the central 0.1 x 0.1’’ in the Galactic Center allows tracing stars orbiting the central massive black hole SgrA. Serving as test particles in a strong gravitational field, these S-stars are susceptible to effects of General Relativity. With its unmatched astrometric precision, the interferometric beam-combiner GRAVITY has already facilitated in the past a measurement of the Schwarzschild Precession and Gravitational Redshift of a bright S-star. This leaves the constraint of the spin of SgrA as a current quest. However, the effect of the Lense-Thirring precession on stars caused by the spin of SgrA drops off steeply with distance, demanding that stars orbit on short periods to be measurable for GRAVITY. In currently accessible magnitudes, no comparable star has been detected so far, requiring to look ever deeper into the Galactic Center. Existing imaging algorithms like CLEAN, which have been adopted from radio interferometry, are stretched to their limits when reconstructing GRAVITY data.
We present the development and results of the image reconstruction method GRAVITY-RESOLVE ($G^R$), which is designed for finding faint, yet undiscovered stars in the Galactic Center. The development includes an exact model of the Galactic Center, as well as all measured instrumental systematics of GRAVITY, allowing for the construction of an utmost precise forward model. The implemented model and inference are based on Information Field Theory.
The results comprise detections of two new stars in the Galactic Center, one of which could enable the measurement of the constraint on the spin of SgrA in the future.