Complex predictions such as election forecasts or the weather reports often have to be simplified before communication. In astronomical data analysis, researchers are also confronted with the problem of simplifying probabilities. Two researchers at the MPA now show that there is only one mathematically correct way to measure how embarrassing a simplified prediction can be. According to this, the recipient of a prediction should be deprived of the smallest possible amount of information.
The diffuse gas around galaxies is hard to detect, but shows properties which are quite different to the star-forming gas inside a galaxy. Scientists at MPA have used observations from the recent MaNGA survey to study how the ionized gas changes with distance from the center of the galaxy. Adding spectra from multiple galaxies, their study shows that the brightness of the gas decreases, while its temperature increases the further the gas is located from the center of the galaxy.
The stellar discs of nearby spiral galaxies are generally not flat and often show waves and warps. A research team at MPA, together with external collaborators, have revisited question about their origins by analyzing new simulations of spiral galaxy formation. Their study shows that close encounters with satellite galaxies and more distant flybys of massive companions are the most common drivers. However, in some cases, bending patterns in discs can also be driven by the accretion of cold gas.
Observations are beginning to be sensitive enough to see the outskirts of galaxy clusters, where theory predicts interesting features in the dark matter and gas profiles: the so-called splashback and the accretion shock. Scientists at MPA use an analytical model to compute the locations of these features, and shed new light on the underlying physics.
From X-ray and SZ observations we know all major characteristics of the hot intracluster medium (ICM) filling the entire volume of galaxy clusters. However, several important properties are still poorly known, including thermal conduction in the ICM, mediated by electrons. Scientists at MPA have analysed the results of recent simulations including magnetic fields and found that the suppression of thermal conductivity by the so-called mirror instability is in fact rather modest, a factor of ~5 compared to unmagnetized plasma.
An international team of researchers have discovered an extremely rare “double source plane” gravitational lensing system, in which two distant galaxies are simultaneously lensed by a foreground galaxy, as part of the on-going Subaru Strategic Survey with Hyper Suprime-Cam. The team dubbed the system ‘Eye of Horus’ as the system resembles this ancient Egyptian symbol. Such a rare system is a unique probe of the fundamental physics of galaxies as well as cosmology.
Scientists are one step closer to answering the secrets of Dark Energy with the largest three-dimensional map of the universe so far: This map contains 1.2 million galaxies in a volume spanning 650 cubic billion light years. Hundreds of scientists from the Sloan Digital Sky Survey III (SDSS-III) – including researchers at MPA and MPE - used this map to make one of the most precise measurements yet of dark energy. They found excellent agreement with the standard cosmological model and confirmed that dark energy is highly consistent with a cosmological constant.
On 28 October 2016 the Russian Academy of Sciences announced that Prof. Marat Gilfanov, a research group leader at the Max Planck Institute for Astrophysics, is elected to the Academy as a Corresponding Member. The Academy holds elections once every several years. This year 3 new corresponding members in Astronomy joined the Academy, including Prof. Gilfanov.