Astronomers witness a monstrous galaxy consuming its neighbour

Observing a supermassive black hole in the distant Universe, MPA astronomers have discovered that it is in the process of stripping gas from a neighbouring galaxy. The gas is being very quickly turned into stars in the black hole’s host galaxy and is allowing the black hole to grow very quickly. This agrees with theoretical predictions that massive galaxies and black holes form with help from mergers with smaller galaxies and bursts of star formation. more

Astronomy goes to school(s)

The MPA Partner Group at Kyambogo University in Uganda led by Dr. Benard Nsamba carried out their astronomy outreach activities for the first time in selected secondary schools in the Eastern region of Uganda. more

Physics against boredom

Physics against boredom

March 03, 2023

Originally a chemist, Taeho Ryu started studying physics, because he was bored during an extended hospital stay. more

Black hole accretion discs may dance around more slowly than previously thought

Black holes, resulting from the death of massive stars, are some of the most exotic and powerful objects in the Universe. Since even light cannot escape these objects, the quasi-periodic signals coming from the gas falling into the black hole serve as a probe to infer a great deal of information about the black hole and its surrounding environment. The most-commonly observed quasi-periodic signal is thought to originate from the wobbling of hot gas around the black hole, like a spinning top. One problem, though, is that inferred size of this (isolated) corona seemed to be inconsistent with estimations from other observables. With our recent, state-of-the-art computer simulations, involving a more realistic geometry of the accretion flow, we demonstrated for the first time, that the presence of a disc around the corona significantly slows down its precession, relieving much of the tension between this model and observations. These results thus have important implications for studies of black hole properties and how black hole systems form and evolve. more

The lingering imprint of the first cosmic structures

The universe today is host to a vast network of galaxies and an even richer array of invisible dark matter structures. But this was not always the case. The universe was nearly uniform until a time of about 100 million years, when the first cosmic structures gravitationally condensed. These objects were made of dark matter alone and each may have weighed no more than the Earth. Most of these objects do not last long: they rapidly grow and cluster together to form the much larger systems that we know today. Despite this, scientists at MPA have discovered in high-resolution simulations that some unique features of the first structures survive this process. Their lingering imprint could manifest itself in astronomical observations, yielding clues to the identity of dark matter. more

Gravitational lensing reveals the detailed shape of a galaxy

Einstein’s General Theory of Relativity predicts that large concentrations of mass – such as galaxies – will bend light rays passing nearby, a phenomenon known as gravitational lensing. When a distant galaxy (the lens) lies exactly between us and an even more distant object (the source), the source is distorted and magnified into several images around the lens galaxy. A group at MPA and other institutes used very long baseline radio interferometry (VLBI) to study a gravitational lens system in high resolution. This reveals extreme detail in the lensed images, and provides a new window into the physics of lens galaxies. more

Emission lines from the simulated interstellar medium

All stars in galaxies form in the dense gas of the interstellar medium (ISM). Ionizing radiation from newly born massive stars and supernova explosions lets the gas shine at characteristic wavelengths of certain atoms and ions. The relative strength of such line fluxes is an important observational diagnostic to reveal the internal state and composition of the ISM. However, emission by diffuse ionized gas has different flux ratios making accurate predictions difficult. Scientist at MPA and their European collaborators have used supercomputers to simulate a realistic star forming interstellar medium and to quantify the contribution of the diffuse gas. This finding allows for a more accurate interpretation of observations also at early cosmic times when these extreme conditions are more common than in the local Universe.  more

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