Helmer Koppelman wins MERAC prize 2022

The 2022 MERAC Prize for the Best PhD Thesis in Theoretical Astrophysics is awarded to Helmer Koppelman for his multi-faceted approach to the field of galactic archaeology that transformed our understanding of the history and dynamics of the Milky Way.

Dr Helmer Koppelman studied astrophysics at the University of Groningen, obtaining his MSc in 2016 “ cum laude ” with a thesis on the evolution of gaps in cold stellar streams. Dr. Koppelman defended his PhD thesis at the University of Groningen in 2020 with the judicium "cum laude". In his remarkably extensive and broad thesis, Dr Koppelman combined theory, simulations, and vast datasets to yield new light on the structure and dynamics of the Milky Way halo and revolutionary new insights on its formation history. He spent a postdoc at the Institute for Advanced Study in Princeton and moved back to the Netherlands to start a new career as data scientist in an international company.

Dr Koppelman has produced an outstanding thesis on the formation and dynamics of the Galactic halo. The thesis offers new insights on how the Milky Way formed based on the newest datasets available and presents new modelling efforts and provides also a new characterization on the properties of dark matter halo of the Milky Way. Using Gaia DR2 data he discovered of a blob of stars that make up the local Galactic halo, which has been interpreted in terms of a large merger event that took place about 10 Gyr ago.

He further pushed the boundaries by fully exploiting the whole Gaia DR2 dataset, using the 1.3 billion stars with proper motion information to construct the biggest sample of halo stars currently available. Using data-mining tools, Dr Koppelman obtained the most precise lower limit to the mass of the Milky Way. In his thesis he further investigated the use of orbital frequencies to understand the gaps in narrow stellar streams, with as goal to put limits on the presence and properties of (dark matter) clumps in the halo.

Dr Koppelman's thesis excelled in the rigor of the analysis and detailed attention to uncertainties while keeping the broad overview of the scientific results and implications. Whereas most of the techniques were known, they were applied in rigorous way to totally new data with careful inference supported in an innovative way by insights from numerical simulations.

The PhD thesis of Dr Helmer Koppelman was conducted at the Kapteyn Astronomical Institute (Univ. of Groningen), under the supervision of Profs. Amina Helmi and Eline Tolstoy.

Source: European Astronomical Society