Peculiar white dwarf mergers

Two types of hot, blue and dense stars that show peculiar characteristics in their composition and vibrations have posed a challenge to astrophysicists for more than a decade. A team of scientists from MPA and La Plata in Argentina, has now been able to explain both types as a product of very similar merger events. In particular, the scientists think that the peculiar hot and blue stars are formed by the merger of two white dwarfs. more

New analysis strengthens the hint of new physics in polarized radiation from the early Universe<br /> 

In 2020, a tantalizing hint of new physics violating “parity symmetry” was found in polarization data of the cosmic microwave background obtained with the Planck satellite at high frequencies. Based on the Planck data and a simplified assumption about the impact of the polarized dust emission in the Milky Way, the scientists reported a violation of the symmetry of the laws of physics under inversion of spatial coordinates with 99.2% confidence level. An international team led by MPA director Eiichiro Komatsu has now improved the analysis method. By considering the dust emission explicitly and using more data from not only Planck but also from WMAP the astrophysicists measured the parity-violating signal with 99.987% confidence level. If this should be confirmed in the future as a genuine cosmological signal, it would have profound implications for the fundamental physics behind dark matter, dark energy, and quantum gravity. more

Dancing pattern of red supergiant stars on the sky

The bubbling surface of massive giant stars causes their observable positions on the sky to wobble. An international team of astrophysicists has now performed detailed simulations of the gas motions in the atmospheric layers of these stars and compared these with high-quality data of the Perseus stellar cluster. They find that the surface structures could indeed account for a large part of the measurement uncertainty in the observations. more

Biermann Lectures 2022: Insights on the Milky Way’s history and dynamics

By Prof. Dr. Amina Helmi (Kapteyn Astronomical Institute, Groningen). more

Reflected quasar light powers giant cool gas nebulae

Already in the early Universe, supermassive black holes with masses a billion times larger than the Sun appear to inhabit the centres of massive galaxies. As interstellar gas is accelerated in their powerful gravitational field, it emits copious amounts of radiation, outshining the entire galaxy as “quasars”. Recent observations have revealed that the first quasars are often surrounded by bright, giant nebulae. These can span up to several 100,000 light years, about ten times larger than their host galaxy. New detailed computer simulations of galaxy evolution performed at MPA have shed new light on these puzzling observations, reproducing them in striking detail. According to these new theoretical models, the observed extended nebulae can be explained as quasar light that reflects off cool neutral hydrogen clouds surrounding the quasar host galaxy. Crucially, this mechanism only works if the energy provided by the quasar is able to produce gigantic galactic winds that blow out large masses of gas from its immediate vicinity. This finding suggests that quasars shape galaxy evolution from the earliest stages of galaxy formation. more

Everything flows

Everything flows

April 05, 2022

Both in her research and her hobbies, Deepika Bollimpalli, is always in motion. more

Do massive red elliptical galaxies line up?

Are galaxy orientations distributed randomly in the cosmos? What appears to be a simple question might not only shed light on our understanding of galaxy and cluster formation, but also further our knowledge of cosmological models. MPA scientists and collaborators attempt to settle this question through the first direct, field-based measurement of whether and how massive red elliptical galaxies align with the tidal field of large scale structure. Their result confirms predictions of the (linear) alignment model of galaxy intrinsic alignment. The newly presented method also opens up new avenues for cosmology and astrophysics. more

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