Intermediate mass black holes (IMBH) should be linking observed stellar black holes and supermassive black holes, but their formation mechanisms are still debated. Young and dense massive star clusters are promising environments for the formation of such black holes through collisions. An international team lead by MPA researchers has presented novel realistic simulations of star clusters, where these missing links form by rapid collisions of stars and black holes. The study also predicts an IMBH formation channel by the merging of black holes in a mass regime, which is excluded by stellar evolution models. In this “mass gap” a black hole merger has indeed been observed recently by the LIGO/Virgo gravitational wave collaboration. more

Where are the baryons? This question naturally arises as the predicted abundance of baryons in the universe - the basic building blocks of all elements in the periodic table – do not agree with observations of the intergalactic medium. Locating the missing baryons will help us to not only better understand the formation and evolution of galaxies, but also to better constrain possible extensions of the current standard model of cosmology. MPA researchers have turned to a novel approach in modelling the galaxy distribution to optimize measurements of the kinematic Sunyaev-Zel'dovich effect, an emerging tool to probe the distribution of baryons in galaxy clusters. more

The Max Planck Society has appointed Simona Vegetti at MPA to head a Lise Meitner Excellence Group. Simona Vegetti will use strong gravitational lensing observations to measure the abundance and structural properties of dark matter haloes and thereby provide clean observational constraints on the nature of dark matter. As part of the programme, the group is endowed with an internationally competitive budget for material and human resources. more

How can machine learning methods help us understand our tangled cosmic web? A new study presents a ‘deep learning’ framework to shed light onto the physics of the formation of dark matter halos. The results show that spherical averages over the initial conditions of the Universe carry the most relevant information about the final mass of halos. more

Galaxy clusters are dynamic systems that grow by continuously accreting large and small chunks of matter. This accretion process should give rise to a rich substructure in the dark matter distribution within the clusters and to shocks and “cold fronts” in the hot baryonic gas. Recent SRG/eROSITA observations provided an unprecedented X-ray view of the Coma cluster, revealing intricate signatures of the merger process, which are predicted by numerical simulations. more

The first all-sky survey performed by the eROSITA X-ray telescope on-board the SRG observatory has revealed a large hourglass-shaped structure in the Milky Way. These “eROSITA bubbles” show a striking similarity to the Fermi bubbles, detected a decade ago at even higher energies. The most likely explanation for these huge features is a massive energy injection from the Galactic centre region in the past, leading to shocks in the hot gaseous halo around our galaxy. more

Stars, stars, stars

January 01, 2021

Selma E. de Mink appointed as director at the Max Planck Institute for Astrophysics more

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