Phd Projects at CAS

PhD Project in Theory

Regions of the interstellar medium filled with atomic and molecular gas are the environments where the first stages of star formation occur. The nested hierarchical structure of molecular gas distribution, from diffuse giant clouds of up to hundreds of pc, through denser ~10 pc clouds and pc-sized clumps, down to very dense sub-pc cores, has a complex filamentary shape. Impressive recent progress in observing molecular gas and dust at different spatial scales has greatly improved our understanding of the density distribution in such environments. Combining these observations with sophisticated models of radiative transfer and applying recent advances in the theory of cosmic ray (CR) propagation in molecular gas makes it possible to self-consistently compute detailed physical and chemical structure of molecular clouds.

CRs are the main source of ionization of molecular gas. Interaction of the ionized hydrogen with neutral hydrogen molecules quickly leads to the formation of H3+ ions. These ions, in turn, trigger a chain of chemical reactions between charged and neutral gas species, producing several other key molecules. The ongoing activity of the CAS Theory Group in studying the CR transport and applying these models to nearby diffuse molecular clouds has delivered all essential ingredients necessary to start exploring the first stages of gas-phase chemistry in these objects.

We offer a Ph.D. position with the topic of CR-driven chemistry in diffuse molecular clouds. The work will be carried out at the interface between the CR theory and astrochemistry. It will be focused on analyzing observationally constrained ionization in nearby molecular clouds, applying and developing available chemical models to compute the formation of key molecular species in these regions, and providing predictions for future dedicated observations. The Ph.D. candidate will work in close collaboration with the members of CAS-Theory group, and will obtain necessary support and complementary advice from experts in astrochemistry and observations.

Supervisor: Dr.  Alexei Ivlev


PhD Project in Laboratory

The detection of ions and radicals of complex organic molecules in the interstellar medium (ISM) will put very stringent constraints on a series of interconnected processes like the development of the molecular complexity in the ISM, and the interplay between gas and dust in the formation of complex organic molecules. This is crucial to unveil the complicated interplay between the chemistry happening in the gas phase and on the surface of dust grains, leading to the molecular complexity that we observe in space, and eventually forming the first bricks for the emergence of life. This PhD project will be focused on the spectroscopy of molecules of astrophysical interest, in particular complex organic molecules as well as their radicals and ions. The PhD candidate will have the opportunity to work with several state-of-the-art experiments such as a sub-millimetre free-unit jet (CASJET, see picture below), a discharge absorption cell (CASAC, see picture below), and a chirp-pulsed spectrometer (CAS Labs). The thesis project will be mainly focus on the acquisition and analysis of spectra that will help the identification of new molecules in the ISM. Furthermore, there will be the possibility to participate to the further development of the experiments, as well as work with astronomical data. Supervisor: Dr. S. Spezzano

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