Research Highlights

On this page you can find a monthly updated list of short articles highlighting current MPA research topics.

Current Research Highlights

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Where are all of the nebulae ionized by supersoft X-ray sources?

February 01, 2016
The ultimate fate of low-mass stars, like our own Sun, is to exhaust the nuclear furnace in their cores, expel their extended atmospheres, and leave behind a hot remnant called a white dwarf. Left to their own devices, these objects will simply cool slowly over billions of years. However, if a white dwarf comes to accrete material from some stellar companion, it can become an incredibly luminous source of extreme UV and soft X-ray emission, a “supersoft X-ray source” or SSS. Such radiation is readily absorbed by any surrounding interstellar gas, producing emission line nebulae. Therefore, we would expect such nebulae to be found accompanying all supersoft X-ray sources. However, of all SSSs found in the past three decades, only one has been observed to have such a nebula. Clearly, something is amiss in our understanding of these incredible objects. Now, scientists at MPA and the Monash Centre for Astrophysics have pieced together the puzzle. [more]
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The diversity of stellar halos in massive disk galaxies

January 01, 2016
The stellar halos of galaxies are diffuse and faint components which provide scientists with a window into the assembling history of galaxies. A research team at MPA has investigated the properties of stellar halos in large disk galaxies by using both observations and state-of-the-art simulations of galaxy formation. They find a great diversity in the halo properties for galaxies that are – otherwise – alike in terms of morphology, mass, and luminosity. Observed properties, such as a mean metallicity as a function of galactocentric distance, can be reproduced by the simulations if they are analyzed in the same way as the data. [more]
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How supernova explosions shape the interstellar medium and drive galactic outflows

December 01, 2015
With complex hydrodynamical simulations scientists at MPA investigate the detailed impact of supernova explosions on the chemical composition and the thermodynamic properties of the interstellar medium and galactic outflows. [more]
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The Distribution of Atomic Hydrogen in Simulated Galaxies

November 01, 2015
In simulated galaxies of the hydrodynamical cosmological “EAGLE” simulation the distribution of atomic hydrogen agrees with observations in unprecedented detail. This success means that EAGLE can aid astrophysicists to better understand the processes shaping real galaxies, such as the origin of their atomic hydrogen. EAGLE is not quite perfect, however: the study also found that some simulated galaxies contain unphysically large holes in their atomic hydrogen discs, meaning further work for simulators to improve the models underlying the treatment of supernova explosions and the interstellar matter. [more]
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Solving the hydrostatic mass bias problem in cosmology with galaxy clusters

October 01, 2015
Booming observations of galaxy clusters provide great opportunities for exploring the nature of Dark Energy. At the same time, they post great challenges to scientists. The "hydrostatic mass bias" problem, which leads to a systematic error in estimating the mass of galaxy clusters, is one big limitation when doing precision cosmology with galaxy clusters. Now researchers at MPA have developed a method to correct for it. [more]
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New limits on the spectral distortions of the Cosmic Microwave Background

September 01, 2015
New data from the Planck satellite and the South Pole Telescope on the Cosmic Microwave Background (CMB) combined with a new component separation algorithm developed at MPA give much tighter limits on two parameters measuring the deviation of the CMB from a blackbody radiation. These results can be used to constrain new physics in the very early universe and to study the correlations between the primordial fluctuations on very small and very large angular scales. [more]
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Three-dimensional computer simulations support neutrinos as cause of supernova explosions

August 01, 2015
Latest three-dimensional computer simulations are closing in on the solution of an decades-old problem: how do massive stars die in gigantic supernova explosions? Since the mid-1960s, astronomers thought that neutrinos, elementary particles that are radiated in huge numbers by the newly formed neutron star, could be the ones to energize the blast wave that disrupts the star. However, only now the power of modern supercomputers has made it possible to actually demonstrate the viability of this neutrino-driven mechanism. [more]
 
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