Research

An important step towards the understanding of the star formation process is identifying the initial phases of the collapse, and deuteration is the best proxy for this purpose. This requires to build accurate chemical networks including spin-state chemistry and isomers to be employed in hydrodynamical simulations of magnetized and turbulent collapsing filaments and cloud cores. We work on the development of reliable chemical models to accurately follow the effect of freeze-out, H2 ortho-to-para ratio, and cosmic-rays on the deuterium fractionation to explore its role as chemical clock of such environments. Post-processes of hydrodynamical simulations are used to compare with observational data.

Together with our collaborators in Bologna and Munich we employ observational data from APEX and ALMA to probe the physical and chemical conditions of star-forming regions. In particular, we focus on deuterated tracers, which are thought to provide information about the physical timescale of the star-formation process. Our targets are sources in the early stages of the star-formation process. The main goal is to catch prestellar cores via unique tracers like oH2D+ and probe their masses to see if high-mass prestellar cores do exist and then disentangle between the different theoretical scenarios.

We explore here the chemistry of the ISM in galaxies, both at solar metallicity as well as in metal-poor environments. We focus on the role of CII and on the H2 chemistry. CII is known to be one of the most important coolant in the interstellar medium, and it is considered a powerful tracer for the star formation activity. In addition, it can provide useful insights on the reionization epoch. Cosmological hydrodynamical simulations of galaxies at different metallicities and redshifts, including a proper chemical model which can follow the [CII] evolution, are very important to probe the correlation between [CII] and the star formation rate, and to follow the transition between the different phases of the ISM. The star formation process in metal-poor galaxies and how this correlates with the molecular gas is not yet fully understood. ALMA observations have reported a very inefficient star formation process in this kind of galaxies. It is then very important to perform galaxy simulations which are able to follow the evolution of the molecular gas for different dust grains compositions/distributions, and compare the results with recent observations.

KROME is a package which aims to provide microphysics and chemical networks to be included in hydrodynamical simulations of astrophysical objects. We also work in collaboration with Tommaso Grassi on development of different reduction methods for astrochemical networks, and codes to solve chemistry in different astrophysical problems (e.g. PATMO for planetary atmosphere, Lemongrab for 1D shocks etc.)

The binding energy of molecules on relevant ice mantles represents one of the largest uncertainty in the chemical modelling of star- and planet-forming regions. Accurate ab-initio calculations of the interaction between molecules and dust-grains are poor, and often performed with strong approximation (e.g. assuming a single water) or low-level of ab-initio methods. In collaboration with Stefan Vogt (Chemistry Department, UdeC) we started the ambitious project to build an accurate database of binding energies on relevant astrophysical surfaces with reliable quantum ab-initio methods. At the same time we are also developing a multi-binding energy approach for chemical models, motivated by the energy distributions found from our chemistry calculations.

We are developing an active nanoparticle mass spectrometer under ultra-high vacuum and cryogenic conditions, to re-create in lab the typical conditions of dark clouds. This involves the construction of a Paul trap, where an individual particle can be trapped via the application of a RF potential. Once trapped the particle can be characterized and its asbolute mass determined. Through the measurement of the mass-difference once a gas molecule is deposited on the particle, we can measure the binding enenergy in a typical temperature-programmed desorption experiment. See more details here.

Within this project we built a 1D chemo-thermal model to study the atmosphere of an exomoon belonging to a free-floating planet. We make use of our private code PATMO.