Cosmology News

Recently, in correspondence with the 10th birthday of LOFAR, a core group of researchers including MPA scientists published the most stringent upper limits on the reionization signal from the early Universe. These observations are able to exclude some reionization models and constrain the thermal and ionization state of the intergalactic medium when the Universe was still in its infancy. more

Extracting cosmological information from galaxy surveys is a difficult task – one to which MPA researchers are now one step closer. Using a theoretical framework known as effective field theory combined with a novel statistical approach, they were able to correctly recover the input cosmology based on a catalog of simplified simulated galaxies. more

A new model of galaxy formation will help scientists to better understand the distribution of gas and stars within galaxies. Researchers from the MPA in Garching, along with collborators from Switzerland, China, the UK, and Iceland have come together to release L-GALAXIES 2020, the latest version of the L-GALAXIES model project, a computational simulation designed to study many millions of galaxies simultaneously, each self-consistently evolved over billions of years of cosmic time. more

Rather than trying to study special regions in large-volume simulations, scientists at MPA have used the IllustrisTNG model to create whole separate universes with a modified cosmology. Their study of these separate universes shows that when the baryon density (the density of ordinary matter) changes, the number of galaxies can increase or decrease depending on how this number is measured. Also, the large-scale distribution of matter is affected by the effects of baryons, with various measures reacting differently. more

Quasars are amongst the brightest non-transient sources in the sky. Thanks to their high luminosity, they can be observed even at early cosmic times, where – surprisingly – these first quasars appear as already evolved systems: with black holes with masses exceeding one billion solar masses hosted by massive and heavily star forming galaxies. To explain such rapid growth, theorists believe these systems must reside in peculiarly dense environments, where huge gas reservoirs favour efficient inflow of material onto seed super-massive black holes. An international team of astronomers has recently found the first clear observational evidence that this is indeed the case. The new “panoramic” spectrograph called MUSE unveiled, for the first time, the almost ubiquitous presence of large amounts of cool gas in close proximity to the first quasars. This pristine fuel will fall on the primordial galaxies and sustain their growth in both stellar and black hole mass. more

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