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Leibniz Institute for Astrophysics Potsdam
Country: Germany
20 Projects, page 1 of 4
  • Funder: EC Project Code: 303912
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  • Funder: EC Project Code: 101020943
    Overall Budget: 2,459,120 EURFunder Contribution: 2,459,120 EUR

    This project aims at developing a radically new view on the structure and dynamics of gas flows in the surroundings of galaxies, a domain known as the circumgalactic medium (CGM). In the last years it became clear that the CGM is crucial for our understanding of galaxy evolution, which are largely shaped in the CGM by the interplay of inflows from the intergalactic medium and outflows driven by supergalactic winds. I plan to investigate the CGM of normal galaxies by means of integral field spectroscopy, or spectro-mapping, in various emission lines. I bring privileged access to two new major astronomical facilities, MUSE on the ESO Very Large Telescope in Chile, and HETDEX on the 10m Hobby-Eberly Telescope in Texas. These instruments are both unique in their capability of performing integral field spectroscopy over unprecedented fields of view, delivering high-quality spectro-mapping information for hundreds of galaxies and their circumgalactic environments simultaneously. I have a leading role in both, and I am the only astronomer in the world with direct access to MUSE Guaranteed Time Observations and to the entire HETDEX survey. The major challenge for this experiment is the extreme faintness of the CGM emission, which so far made spectro-mapping unfeasible except for a few extreme objects. My recent breakthrough discoveries with MUSE of ubiquitous Lyman-alpha haloes around high-redshift galaxies demonstrate that finally we have achieved the sensitivity required to detect the CGM directly in emission through imaging spectroscopy. I now want to go a big step beyond and apply this approach to large representative samples of typical galaxies at all redshifts. My goal is not only to detect and establish line emission from the CGM as a universal phenomenon, but to disantangle its complex substructures and, through comparisons with physical models and the latest numerical galaxy formation simulations, build a comprehensive picture of these processes.

  • Funder: EC Project Code: 682115
    Overall Budget: 1,985,020 EURFunder Contribution: 1,985,020 EUR

    The Magellanic Clouds are the nearest gas-rich dwarf satellites of the Milky Way and illustrate a typical example of an early phase of a minor merger event, the collision of galaxies that differ in mass by at least a factor of ten. In spite of their important role in supplementing material to the Milky Way halo and the numerous investigations made in the last decade, there remain several uncertainties. Their origin is still a matter of debate, their satellite status is unclear, their mass is uncertain, their gravitational centres are undefined, their structure depends strongly on stellar populations and is severely shaped by interactions, their orbital history is only vaguely associated to star forming events, and their chemical history rests upon limited data. This proposal aims to remedy this lack of knowledge by providing a comprehensive analysis of the stellar content of the Magellanic Clouds and dissect the substructures that are related to their accretion history and the interaction with the Milky Way. Their internal kinematics and orbital history, establishing their bound/unbound status, will be resolved thanks to the analysis of state-of-the art proper motions from the VMC survey and the Gaia mission, and the development of sophisticated theoretical models. Multi-wavelength photometric observations from ongoing large-scale projects will be analysed together to characterise the stellar population of the Magellanic Clouds as has never been previously attempted, including the effects of separate structural components. New large-scale spectroscopic survey projects in preparation will resolve metallicity dependencies and complete the full six-phase space information (distance, position, and motion). This proposal will have a tremendous impact on our understanding of the consequences of minor mergers, and will offer a firm perspective of the Magellanic Clouds.

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  • Funder: EC Project Code: 101043302
    Overall Budget: 2,437,490 EURFunder Contribution: 2,437,490 EUR

    The aim of this ambitious research project is to produce the most realistic computer simulations of the assembly of gaseous protoplanetary accretion discs, and to understand which of their traits are inherited from and/or affected by their direct interstellar context. Owing to ground-breaking instruments such as VLT/Sphere or the ALMA telescope array, we now have a first extensive census of disk populations. Moving beyond the core characterisation of relatively isolated disks in the calm Class II stage, the time has come to shift the focus towards the wider context of these systems, that is, the actively star-forming stellar associations, such as the archetypal Taurus, Orion or Lupus regions. Stellar ages of disks with substructure of (likely) planetary origin point to the fact that planet formation is not merely an ubiquitous process, but figuratively speaking happens within the blink of an eye. This mandates to abandon the assumption of the disk as a quiescent entity detached from its surroundings, and instead place it in the context of a collapsing cloud core. Key aspects here are i) the external UV radiation field that can drive powerful photochemical reactions on the surface, ii) perturbations from stellar flybys, iii) gas self-gravity, and iv) magnetic field lines that are self-consistently anchored in the local interstellar medium (ISM); the latter aspect requiring adaptive-mesh technology, provided by the NIRVANA III code, co-developed by the applicant. At the same time, the early appearance of planets poses questions about the solid constituents potentially being inherited from the ISM and “primed” during the protostellar precursor phase. Finally, with the pivotal exchange of angular momentum during the collapse regulated by non-ideal MHD effects, the evolution of microphysical coefficients (i.e., through an ionisation chemistry with recombination on small grains) needs to be followed through the collapse phase, accounting for dust growth by coagulation.

  • Funder: EC Project Code: 885990
    Overall Budget: 162,806 EURFunder Contribution: 162,806 EUR

    To understand how the first galaxies formed, we need to characterise their properties. Studying these galaxies directly is challenging, as they are hard to detect in emission. Another way of understanding galaxies in the early Universe is through their interactions with the cosmic web of gas surrounding them, which is observed as absorption lines in the spectra of distant quasars. By studying the ionization state and chemical enrichment of this gas, we can put constraints on theories of galaxy formation. During this fellowship, hosted at the Leibniz-Institut für Astrophysik Potsdam, I will use radiative transfer and hydrodynamic cosmological simulations to model the connection between galaxies and the intergalactic medium (IGM). This research will combine my skills in modelling the IGM with the expertise of my supervisor Prof. Dr. Christoph Pfrommer in the physical processes that drive galaxy outflows. The novel aspect of my work is that I will simultaneously model the evolution of the intergalactic medium on large scales, and the physics driving galaxy formation on smaller scales. In particular, I will focus on modelling metal absorption lines, which are a signature of galactic outflows. Typically, interpreting these metal lines is hard, due to the degeneracy between the ionization state of the gas and its metallicity. I will break that degeneracy by carefully calibrating the ionization state of the simulations against existing data from the Lyman-alpha forest. This will allow me to constrain the efficiency of galactic outflows, and to understand the nature of the galaxies that enriched the IGM with metals. I will construct mock observations from my simulations to make direct comparisons with real data, testing models of galaxy formation and constraining the timing of reionization. My results will be essential for interpreting existing and forthcoming observations, as well as for making predictions for the next generation of 30-metre telescopes.

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