Seminars and Colloquia at ESO Garching and on the campus

It is now commonly accepted that stars are mainly born multiple. Half of all field stars belong to multiple stellar systems, a number that is even higher at younger ages. Thus, multiple stellar systems are rather the norm than the exception. Despite being of key importance, the impact of stellar multiplicity on how planets form remains poorly understood.

Indeed, protoplanetary discs in multiple stellar systems are subject to gravitational perturbations from surrounding stars, which alter their kinematics and can lead to complex dynamical behaviours. Stellar multiplicity also imprints a variety of sub-structures in protoplanetary discs (cavity, spiral arms, …). These sub-structures can take the form of high-density regions that may locally promote dust growth. Conversely, stellar multiplicity can excite high collisional velocities between dust grains, hindering their growth. The way these barriers are overcome remains elusive.

In this talk, we will study the dynamics of discs in multiple stellar systems following the example of V892 Tau. Then, we will examine the properties of dust grains in young multiple stellar systems mainly based on sub-millimeter/millimeter observations. After that, we will see how hydrodynamical simulations can predict the grain properties in these complex environments, linking the simulated disc dynamics to the observed grain properties. With numerical results connecting well to the observations, I will conclude by discussing the implications for planet formation in multiple stellar systems.

To address the need for a more realistic comparison between theory and observations, this talk will describe the creation of a synthetic spectroscopic dataset derived from the TNG50 cosmological simulation, tailored for WEAVE-StePS observations. I will compare the star formation histories of these galaxies, obtained through a full spectral fitting analysis, with their merger histories derived from the simulation. This strategy allows for a proper comparison between observed star formation histories and those inferred from cosmological simulations, highlighting potential systematics and observational biases.
This analysis serves as a fundamental benchmark not only for the forthcoming WEAVE observations but can also be easily generalized to any facility worldwide, providing the community with realistic mock galaxies to compare against observed datasets and explore optimal strategies for future extragalactic campaigns.
In the second part of the talk, I will focus on how to utilize simulations when studying star formation histories (SFH) in different environments. My project at the European Southern Observatory (ESO) aims to assess the role of the environment in shaping the SFH of galaxies by comparing data from various clusters in the local universe. The project is divided into two main aspects: analyzing observational data and comparing it with simulations.
We have already analyzed publicly available archival ESO data, such as Atlas3D (Cappellari et al., 2011) for the Virgo cluster and Fornax3D (Sarzi et al., 2018) for the Fornax cluster. While these observations provide a snapshot of the present-day universe, cosmological simulations offer comprehensive insights into the merger history, quenching, and rejuvenation processes of each galaxy. This work aims to uncover the physical processes that lead to specific SFHs, emphasizing the importance of an "apples-to-apples" comparison between observations and simulations.