Current Research Highlights

<span><span><span><span>Unveiling the Universe at the field level</span></span></span></span>

The distribution of galaxies on large, cosmological scales holds important clues on the nature of dark matter, the properties of dark energy and the origin of our Universe. Yet, optimally retrieving this information from observations is challenging. MPA researchers are developing a novel analysis approach, where they follow the evolution of cosmic structures through their entire formation history. Enabling a very detailed comparison between theoretical models and observational data, this approach will allow measuring key parameters of dark matter and dark energy very precisely. more

Probing Cold Gas with the Resonance Doublet of Singly Ionized Magnesium<br /> 

Traditional studies of the gas around galaxies rely in particular on absorption and emission features of neutral hydrogen, the simplest and most abundant element in the universe. MPA researchers have now investigated alternative tracers, in particular the resonance doublet of singly ionized magnesium and found that analyzing this emission can lead to significant advances in studying the circum-galactic medium. They showed the potential of the magnesium doublet as an alternative to Lyman-alpha emission through a new radiative transfer code and suggest that the magnesium doublet ratio could even be used as a tracer of the Lyman-continuum escape. more

A new spin on Betelgeuse’s boiling surface

Betelgeuse is a well-known red supergiant star in the constellation Orion. Recently it has gained a lot of attention, not only because variations in its brightness led  to speculations that  an explosion might be imminent, but also because observations indicated that it’s rotating much faster than expected. This latter interpretation is now put into question by an international team led by astronomers at Max Planck Institute for Astrophysics, who propose that Betelgeuse’s boiling surface can be mistaken for rotation even in the most advanced telescopes. Other astronomers are actively analyzing new observational data to test such hypotheses. more

What happens when a star approaches a black hole?

In dense stellar environments, interactions between stars and stellar-mass black holes should occur frequently. Through hydrodynamical simulations, researchers at MPA have explored how stars are disrupted in such encounters, varying key parameters such as stellar and black hole masses, stellar age, and approach distance. The study quantifies the impact of these initial parameters on stellar remnants' masses, spins, and trajectories, offering insights into cluster dynamics and providing best-fit formulae for post-disruption parameters. more

Our Neighborhood in the Milky Way in 3D

High-resolution three-dimensional maps of the Milky Way have previously been limited to the immediate vicinity of the Sun. In a collaboration led by the Max Planck Institute for Astrophysics with researchers from Harvard, the Space Telescope Science Institute, and the University of Toronto, we were now able to build a high-resolution map of the Milky Way in 3D out to more than 4,000 light-years. The produced 3D map will be highly useful for a wide range of applications from star formation to cosmological foreground correction. more

Magnetic fields in multiphase gas: A turbulent tango

Space is filled with gases of vastly different temperatures and it is important to understand how these interact. A group of scientists at MPA has now looked into the mixing of gases with and without magnetic fields. Surprisingly, they find that the outcome depends on whether turbulence is already present at the beginning. Without turbulence, magnetic fields can suppress the mixing by suppressing turbulence, while if the turbulence is already present, magnetic fields have a marginal effect. more

SPICE connects stellar feedback in the first galaxies and cosmic reionisation

The first billion years saw the transformation of a cold neutral Universe to a hot and ionised one. This Epoch of Reionisation is thought to come about from stellar radiation from the first galaxies. Understanding the nature of the galaxies that drove reionisation remains a key question. Scientists at MPA have designed a novel suite of simulations to systematically understand how different modes of energy and mass injection from stars affect the first galaxies. According to these new models, subtle differences in the behaviour of stellar feedback drive profound differences in the morphologies of galaxies and the speed at which they ionise the universe. Combining these findings with the latest observations will help constrain feedback models in the first billion years of the Universe. more

Most energetic stellar collisions in the Universe

In dense stellar environments, stars can collide. If there is a massive black hole nearby – at the centre of galaxies – these collisions can be so energetic that the two stars are completely destroyed upon collision, leaving behind an expanding gas cloud. While the collision itself can generate a very luminous flare for several days, there might be an even brighter flare that can last up to many months, as the gas cloud is captured by the nearby black hole. A research team led by MPA has estimated the observables of such powerful events for the first time using the two state-of-the-art codes AREPO and MESA, developed at MPA. more

What happens when you put a star inside a star?

Throwing one star into another into another star does not bode well for either star. However, given the right conditions and the right types of stars this can lead to the stars merging and forming one single object. If one of the stars is a neutron star (the dense stellar remnant after a supernovae) it can sink to the center of the other star replacing that star’s core. Such objects are called Thorne-Żytkow objects (TŻOs) as they where first proposed by Kip Thorne and Anne Żytkow. Now an international team of astrophysicists led by the Max Planck Institute for Astrophysics (MPA) has re-evaluated what these TŻOs look like and whether we can find them. more

Effects of Neutrino Fast Flavor Conversions on Core-Collapse Supernovae

Neutrinos are the driving factor for core-collapse supernovae, the violent death of massive stars. According to the neutrino-driven mechanism they are responsible for transferring energy from the hot proto-neutron star (PNS) to the surrounding material. So far, numerical simulations assumed that neutrinos retain their flavor during propagation. Max Planck researchers have now shown that allowing for flavor conversions has a direct influence on the supernova dynamics. more

If dark matter is fuzzy, then how fuzzy is it?  - A gravitational lens has the answer

Dark matter, which makes up over 80% of the mass in the Universe, does not absorb or emit light, interacting with light and normal (baryonic) matter only through its gravitational pull. The nature of dark matter is one of the major open questions in astrophysics and cosmology. One theoretical model for dark matter, known as fuzzy dark matter (FDM), is predicted to leave a very specific imprint on light that is bent around a massive galaxy in a phenomenon called gravitational lensing. By examining the radio light in a gravitational lens system observed at extremely high angular resolution, we have determined just how “fuzzy” the dark matter can be. more

Manipulative communication in humans and machines

A universal sign of higher intelligence is communication. However, not all communications are well-intentioned. How can an intelligent system recognise the truthfulness of information and defend against attempts to deceive? How can a egoistic intelligence subvert such defences? What phenomena arise in the interplay of deception and defence? To answer such questions, researchers at the Max Planck Institute for Astrophysics in Garching, the University of Sydney and the Leibniz-Institut für Wissensmedien in Tübingen have studied the social interaction of artificial intelligences and observed very human behaviour. more

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