Toward the mass function of black holes with modern observations of microlensing events

December 4, 2025

When: December 4, 2025 3:30PM

Where: LCO Downstairs Conference Room

Astronomical Observatory, University of Warsaw

Gravitational-wave detectors - LIGO, Virgo, and KAGRA - have revealed a population of massive black holes whose origin is still a subject of vigorous debate. Understanding the population of black holes in the Milky Way is therefore of key importance for understanding and putting into the astrophysical context the LIGO/Virgo/KAGRA discoveries.

Gravitational microlensing remains the only viable technique which enables us to detect and directly measure masses of isolated stellar remnants, especially neutron stars and black holes. In this talk, I will present the recent advancements in the field of gravitational microlensing, which have led to the discovery of the first isolated stellar-mass black hole in the Milky Way and which will pave the way for future similar discoveries. I will present how astrometric and interferometric observations of gravitational microlensing events allow us to detect and characterize isolated neutron stars and black holes. Finally, I will discuss whether black holes of different sizes can make up dark matter.

Przemek Mróz

Przemek Mróz is an adiunkt (assistant professor) in the Astronomical Observatory, University of Warsaw. He received his PhD from the University of Warsaw, where he worked with Prof. Andrzej Udalski, and then worked as a postdoctoral researcher in the Caltech Department of Astronomy under the supervision of Prof. Shrinivas Kulkarni. He is a member of the OGLE and ZTF teams. His research interests include gravitational microlensing, the structure and history of the Milky Way, transients, and variable stars. He has extensive experience in analyzing huge photometric data sets using both traditional and machine-learning-based techniques.

Seminar