Current Research Highlights

Current Research Highlights

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Neutron Stars on the Brink of Collapse

January 01, 2018
Neutron stars are the densest objects in the Universe; however, their exact characteristics remain unknown. Using recent observations and simulations, an international team of scientists including researchers at the Max Planck Institute for Astrophysics (MPA) has managed to narrow down the size of these stars. Thus the scientists were able to exclude a number of theoretical descriptions for the neutron star matter. [more]
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LOFAR radio observations document rejuvenation in space

December 01, 2017
In observations of galaxy clusters, astronomers in collaboration with the MPA discovered a new class of cosmic radio sources. With the digital radio telescope Low Frequency Array (LOFAR) they received the longest radio waves that can be measured on Earth. They identified a remarkable "tail"behind a galaxy in the radio light, which must have been re-energized after it had faded away. In the journal Science Advances, the team describes this discovery, which either confirms a theoretical prediction on the interaction between shock waves and radio plasma or represents a novel phenomenon. [more]
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Bridging the Gap: From Massive Stars to Supernovae in 3D

November 01, 2017
A team of astrophysicists from Queen’s University Belfast, the Max Planck Institute for Astrophysics (MPA), and Monash University (Australia) has, for the first time, performed three-dimensional computer simulations that follow the evolution of a massive star from its final phase of nuclear burning, through the collapse of the stellar iron core, into the first seconds of the beginning explosion as a supernova. The simulations show that the large-scale violent convective motions that stir the oxygen burning layer at the onset of collapse can provide crucial support for the explosion of the star. [more]
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Rise and Shine: Type Ia supernova models at early times

October 01, 2017
Type Ia supernovae (SNe Ia) are spectacular explosions in white dwarf stars and play an essential role in astrophysics in general and in cosmological studies in particular. However, many puzzles about the nature and the inherent physical mechanisms in SNe Ia are still waiting to be answered. Robotic surveys of the next decade will provide an unprecedented wealth of observed Type Ia supernovae, detected shortly after explosion. Researchers at MPA examine here whether different explosion models are expected to leave clear imprints in such early observations that could be used in future photometric surveys to help shedding light on the progenitors and explosion mechanism of SNe Ia. [more]
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Probing molecular clouds with supermassive black hole X-ray flares

September 01, 2017
The centre of the Milky Way is a very special place, harboring many exotic objects, such as the supermassive black hole Sagittarius A* and giant molecular clouds. Some of these clouds, despite being cold, are sources of high energy photons. It is believed that the clouds are not producing these photons themselves, but rather scatter the X-ray radiation coming from outside.  Even though Sgr A* is currently very faint in X-rays, it is considered as the main culprit of this radiation, in the form of short but intense flares, which happened over the past few hundred years. The time delay caused by light propagation from Sgr A* to the clouds and then to us, allows one to study Sgr A*’s past activity. At the same time, flares serve as an extremely powerful probe of molecular gas properties. In particular, the full 3D structure of molecular clouds and their density distribution on small scales can be reconstructed. [more]
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Instabilities in relativistic magnetized accretion disks

August 01, 2017
Using three-dimensional general relativistic magnetohydrodynamic simulations, scientists at the Max Planck Institute for Astrophysics (MPA) have studied thick accretion disks orbiting around black holes. They find that weak magnetic fields can suppress the development of large-scale over-densities in the accretion flow. The onset of magnetic turbulence reshapes the disk's structure and could even quench the gravitational-wave signal produced by the accreting torus without magnetic fields. [more]
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Wanted: the rotating radio emission of the Milky Way

July 01, 2017
The magnetic fields of the Milky Way cause electrons with nearly the speed of light to rotate and to emit radio waves. As consequence, this radiation should also "rotate" slightly, it is circularly polarized. This very weak circular polarization of the Milky Way, however, has not been observed so far. Researchers at the Max Planck Institute for Astrophysics and colleagues have now predicted some properties of this polarization and created a "wanted poster" to allow targeted searches. A measurement of the circular polarization would provide important insights into the structure of the galactic magnetic fields and confirm that electrons - and not positrons - are the source of this radio emission in the Milky Way. [more]