KETJU
The KETJU project, funded by the European Research Council (ERC) and the Academy of Finland (AoF), studies the dynamics and impact of supermassive black holes using numerical simulations. The code that enables these simulation is publicly available.
SIBELIUS
The SIBELIUS project, also funded by the Academy of Finland (AoF), investigates the formation and evolution of the Local Group of galaxies in their true cosmic environment by utilising constrained numerical simulations.
Other research topics of our group members include the formation and evolution of stellar clusters, radiative transfer in the vicinity of compact objects, the formation of the first supermassive black holes, and the formation and evolution of massive galaxies.
Latest News
No certainty about the predicted Milky Way - Andromeda collision
Our recent article challenges the status quo of an unavoidable collision between our Galaxy and our nearest neighbour - the Andromeda galaxy. The article has featured in a number of press releases: the University of Helsinki release can be found here.
Published Article: Identifying supermassive black hole recoil in elliptical galaxies
Our article explores the effect an SMBH ejected from the centre of the galaxy through a gravitational wave-induced kick after coalescence has on the surrounding stellar medium. We tackle the problem from both the effect the recoiling SMBH has on the mass density profile of the galaxy, and from the perspective of a change in stellar kinematic structure. We’re able to infer the recoil velocity of a SMBH given the projected mass density of the galaxy and the excess of non angular momentum-conserving orbits in the central regions of the galaxy. We predict that in general, the recoil velocities of coalescing SMBHs is relatively low in massive elliptical galaxies.
Published Article: MAGICS II. Seed black holes stripped of their surrounding stars do not sink
In this article, we study the sinking of seed black holes using simulations that resolve the black hole dynamics in three stages, with KETJU employed at the highest resolution in the final stage. We find that the presence of a bound stellar cluster around the black hole is crucial for it to sink to the center of the galaxy. This study is part of the MAGICS suite of simulations.
Contact
For any enquiries, please contact Prof. Peter Johansson