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Galaxies are the birthplace of most stars and black holes. However, scientists are still debating, how galaxies accrete the fuel to sustain their growth, and how they in turn pollute their environment with elements heavier than helium. An international team of astrophysicists has now directly observed the neighborhood of a massive galaxy in the early universe. They find that the gas all around the galaxy is enriched with heavy elements, which means it has been polluted by the galaxy itself and by embedded satellite galaxies. Furthermore, this gas is spiraling onto the massive galaxy, fueling further star formation. more

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

Galaxy clusters are our universe's largest gravitationally bound systems, extending out to several million light-years and hosting up to 1000 galaxies. The matter permeating the clusters is known as the “intracluster medium” (ICM), a very hot and ionized gas (T~ 10-100 million K) emitting bright X-rays due to thermal bremsstrahlung. Scientists from MPA and the University of Heidelberg have discovered that the ICM also contains a significant amount of cool gas (10,000 K) up to large distances. The statistical connection between the haloes of cluster galaxies and absorption features points toward a complex origin of this cool gas where clouds are either associated with satellite galaxies or were previously stripped from their haloes. more

Galaxies are embedded in large reservoirs of gas - mostly hydrogen and helium. This hydrogen gas has been found to glow faintly in a specific ultraviolet wavelength, or color, called Lyman-alpha. Scientists at the MPA have discovered that these Lyman-alpha halos are larger than previously thought, spanning several 100,000 light years. The inferred size and shape of the halos suggest that the light in the outer parts of the halos comes from surrounding galaxies or the gas in their environments rather than from the central galaxy itself. more

A new study of galaxies with data from the MaNGA survey shows that the initial mass function of stars, i.e. the mass distribution when they initially form, might not be as universal as widely assumed. The MPA study found an excess of very massive stars in some galaxies. An excess of radio sources in the sample might be an intriguing hint that a hidden population of black holes may exist in these galaxies. more