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Di Carlo, Ugo Niccolò (2017) Investigating rotation in young massive clusters by means of hydrodynamical and direct N-body simulations. [Magistrali biennali]

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Abstract

One of the main open questions of star formation is the process of star clusters aggregation. In my thesis I investigate the kinematical features of embedded star clusters through hydrodynamical and N-body simulations. In particular I focus on the onset of rotation. I started from smoothed-particle-hydrodynamics simulations of turbulence- supported molecular clouds with masses ranging from 10000 M to 200000 Msun . In each simulated cloud a star cluster forms by hierarchical assembly of several sub-clumps; during this process torque is exerted on the parent gas and the stellar component because they accrete on the main cluster structure with non-zero angular momentum. This angular momentum is transferred to the main cluster, which acquires significant rotation. I study the dynamical evolution of the cluster that forms in each cloud using direct summation N-body codes, to see how rotation and ellipticity evolve through time. My simulated star clusters start with large ellipticity (e ∼ 0.7 at t = 3 Myr) and with a rotational velocity Vrot ∼ 5 km s^−1 . During their evolution they tend to become rounder (e ∼ 0.2 at t = 10 Myr) and their rotation signature decreases because of two-body relaxation. Rotation is still apparent at t = 20 Myr, so it decreases on a surprisingly long timescale. This result is a key test to probe the hierarchical formation scenario of star clusters, and might be useful to interpret the observed rotation signature in young massive star clusters (R136, Hénault-Brunet et al. 2012) and in old globular clusters (e.g. Bellazzini et al. 2012).

Item Type:Magistrali biennali
Uncontrolled Keywords:Star Clusters – Rotation – Simulations – Hydrodynamics – N-Body
Subjects:Area 02 - Scienze fisiche > FIS/05 Astronomia e astrofisica
Codice ID:57025
Relatore:Piotto, Giampaolo
Data della tesi:17 October 2017
Biblioteca:Polo di Scienze > Dip. Fisica e Astronomia "Galileo Galilei" - Biblioteca
Tipo di fruizione per il documento:on-line per i full-text
Tesi sperimentale (Si) o compilativa (No)?:Yes

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