Johanna Müller-Horn   (Germany)

mueller-horn @ mpia.de

Binary star systems with possible compact companions

Current population synthesis models predict the presence of millions of stellar-mass black holes (BHs) in the Milky Way; however, observational discoveries remain scarce. The formation of BHs, arising from the gravitational collapse of massive stars or as remnants of supernova explosions, is associated with many uncertainties regarding their specific characteristics, such as mass and multiplicity. This uncertainty prompts the need for better observational constraints to enhance our understanding of stellar evolution models and the progenitor population of gravitational-wave events.

While the direct observation of black holes (BHs) poses inherent challenges, the few detections to date have primarily originated from accreting, X-ray bright binary systems. However, it is probable that these represent only the tip of the iceberg of a much larger population of BHs. In my research, I shift the focus towards dormant BHs within detached binary systems. In these systems, the BH induces characteristic variations in the radial velocity, photometric flux, and the position of the light centroid of its luminous companion. These variations provide opportunities for indirect detection, offering a promising avenue to build a more comprehensive understanding of the black hole population in our galaxy.

Supervisor:    Hans-Walter Rix (MPIA)