Dr Aris Tritsis

Australian National University, Australia

The 2020 MERAC Prizes for the Best PhD Thesis are awarded in Theoretical Astrophysics to Dr Aris Tritsis (Australian National University, Australia) for fundamental contributions to the physics of the interstellar medium and the process of star formation.

Dr Aris Tritsis has been a post-doctoral fellow at the Research School of Astronomy & Astrophysics of the Australian National University since 2017. He studied Physics at the University of Ioannina and in 2013 he graduated with a master's degree in Astrophysics from the University College of London. He obtained his PhD at the University of Crete (2014 - 2017) where he worked on the physics of star formation, astrochemistry, and molecular line radiative transfer. He is a member of the SPICA collaboration aiming to launch the cryogenic infrared satellite for the ESA M5 slot.

Dr Tritsis studied a wide range of physical processes, from interstellar chemistry to cloud dynamics and radiative transfer. He made fundamental contributions to the understanding of the physical origin of striations (quasi-periodic, ordered structures in the low-density parts of otherwise chaotic-looking interstellar clouds). He demonstrated that striations are the result of magnetosonic waves, and he confirmed the predictions of this model by discovering normal modes that have been set up in an isolated cloud, the Musca molecular cloud, by these waves. In a highly surprising and impactful discovery, he used these normal modes to reconstruct the 3-dimensional shape of Musca. Tritsis showed that Musca is pancake-like, a sheet seen edge-on. This work received world-wide attention, both by scientists and the general public. Using hydrodynamical numerical simulations coupled with the largest chemical network to date (300 species, 14,000 reactions, gas and grain species), Tritsis identified the best molecules to probe the true 3D shape of cloud cores. Tritsis is also the developer of the line radiative transfer code PyRaTE. He used it to post process the results of his MHD simulations of star forming regions to compare with observations. Since his graduation, based on his PhD thesis results, Tritsis has developed a novel analytical method for measuring the magnetic field strength, taking advantage of the fact that striations are the imprint of hydromagnetic waves. He is currently using this method to create a 3D atlas of the magnetic field strength in the Milky Way.

The PhD thesis of Aris Tritsis was conducted at the University of Crete under the supervision of Prof. Konstantinos Tassis. He was also member of the Astrophysics Group at the Institute of Electronic Structure and Laser of the Foundation for Research and Technology - Hellas.