Astronomers at the Max Planck Institute for Astrophysics, using the Atacama Large Millimeter/submillimeter Array (ALMA), have revealed an extremely distant and therefore very young galaxy that looks surprisingly like our Milky Way. The galaxy is so far away its light has taken more than 12 billion years to reach us: we see it as it was when the Universe was just 1.4 billion years old. It is also surprisingly unchaotic, contradicting theories that all galaxies in the early Universe were turbulent and unstable. This unexpected discovery challenges our understanding of how galaxies form, giving new insights into the past of our Universe. more

About 10 billion years ago, a galaxy smashed into our cosmic home, the Milky Way, in a violent “merger” event that changed the way the Galaxy looks. Researchers from MPA together with international collaborators from the UK, Chile and Italy, have managed to piece together the impact of this event using the largest and most sophisticated simulations of the Milky Way to date. In particular, they found that the damage inflicted on the Galaxy in its youth is commensurate with a satellite that weights about a billion Suns. more

By examining the Auriga suite, a large sample of simulated Milky Way galaxies formed in the full cosmological context, scientists at MPA have been able to place constraints on the history of the Milky Way's formation. By comparing these simulations to observations of the Milky Way — and specifically to how fast stars of different metallicities in the inner regions of the Galaxy move around its centre — they were able to exclude certain formation histories. In particular they found that our galaxy had to be quite isolated with the last major merger happening over 12 billion years ago and with a galaxy less than 10% of the mass of the Milky Way. more

Globular clusters are the densest gravitationally bound stellar systems in the Universe. They are found in all galaxy types, even low mass dwarf galaxies and they can be almost as old as the Universe. The formation mechanisms of these enigmatic systems are not yet understood. Scientist at MPA and the University of Helsinki, together with international collaborators, have now presented the first hydro-dynamical simulation at sub-parsec resolution following the entire formation history of spatially resolved globular cluster candidates in merging dwarf galaxies. This provides a general model for the formation of metal-poor globular clusters in chemically unevolved starbursting environments of low-mass galaxies at high redshifts. more

New cosmological simulations targeting the evolution of the first quasars and their host galaxies now follow the effects of radiation from young stars on the interstellar medium. As the international team shows, stellar radiation can alter both the properties of the quasar host galaxy and its satellites, making them more diffuse and less tightly-bound. Satellites are more easily disrupted by the strong tidal forces of the massive central galaxy, which therefore contains a smaller satellite population. more

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