Cosmological simulations

Until a few years ago, studies of galaxy formation have been affected by uncertainties both in the underlying cosmology as well as in the most relevant physical processes. Now we are in the so called "precision cosmology" era, which means that the background model is relatively well defined by a wealth of observations, in particular those of fluctuations in the cosmic micro-wave background. So, we can compute with reasonable confidence the evolution of the dynamically dominant dark matter (DM) component, ruled by gravity. Starting from a reasonable spectrum of primordial density fluctuations, over-density regions above the linear regime collapse into sheets and filaments. Then, matter mainly flows along filaments into dark matter halos. These halos merge to form bigger and bigger halos (hierarchical clustering).The general outcomes of these gravity-only simulations confirm and deepen those obtained by means of analytical analysis, yielding a broad outline of the formation of cosmic structures: galaxies and clusters. Indeed, a full understanding of the processes leading to the formation of cosmic structures, galaxies in particular, would require the much more demanding task of treating the complex physic of luminous (baryonic) matter. Galaxy formation, which occurs in DM halos, involves a complex web of processes: merging of dark matter halos, cooling of gas, collapse and star formation from cold gas, energy input into gas from SNae explosions and winds (energetic feedback), chemical enrichment of gas and stars (chemical feedback), galaxy mergers, luminosity evolution of stellar populations, absorption of starlight by dust and re-emission in IR+sub-mm, formation of super massive black holes, the ensuing AGN activity and its feedback on the interstellar medium. To follow from first principles all these processes in a fully cosmological context, it would span a dynamical range from << 1pc to >10 Mpc. Moreover, many of processes above are still poorly understood. Thus, simulations genuinely from first principles are at present impossible. Two complementary approaches are usually followed: (i) numerical simulations including gas, i.e. smooth particle hydro-dynamical (SPH) simulations, accounting for phenomenological prescriptions of sub-grid physics (e.g. star formation, feedback, SMBH growth), (ii) semi-analytical models (SAMs), using the prescription approach for every process involving baryons. At the OAPd we are deeply involved in both these projects. In particular, SPH simulations focusing on the bar growth and its evolution, for the first time in a fully cosmological frame , and the first SAM model accounting for the feedback from star formation and AGN activity, have been recently performed. Results from both these approaches help us to shed light on, and may be to solve, several crucial points concerning galaxy evolution.

Cosmological Simulations - PAST STUDIES

News – MEDIA INAF

Il notiziario online dell'Istituto Nazionale di Astrofisica
  • Dal 3 al 5 dicembre, a Washington, una folta delegazione dell’Istituto nazionale di astrofisica ha preso parte ai lavori della Joint Commission for Scientific and Technical Collaboration fra Italia e Stati Uniti

  • Il lander della Nasa ha davanti a sé un anno e 40 giorni marziani di missione e ha già cominciato a lavorare per la delicata fase di posizionamento a terra degli strumenti principali: un sismometro e una sonda termica

  • Fra i compiti che attendono la missione Osiris-Rex, giunta in orbita attorno all’asteroide lunedì scorso, c’è anche quello di misurare con precisione e “dal vivo”, per la prima volta, l’effetto Yarkovsky. Ottenendo così informazioni cruciali per valutare con precisione la probabilità di un futuro impatto di Bennu con la Terra

  • È atteso per questa sera, venerdì 7 dicembre, intorno alle 19:30 (ora italiana), il lancio della missione con cui la Cina punta a portare due mezzi robotici (un lander e un rover) nel cratere Von Karman, sulla faccia nascosta della Luna. Durata prevista del viaggio: 27 giorni

  • Proposto per la Adaptive Optics Facility del Very Large Telescope dell’Eso, Mavis – progetto australiano-europeo – sarà il primo strumento assistito da ottica adattiva multi-coniugata nel visibile. L’Inaf ha la responsabilità del modulo di ottica adattiva e un rilevante ruolo nel team scientifico

  • Nata come lavoro per la tesi di dottorato, la ricerca condotta da Michela Negro – giovane ricercatrice dell’Infn di Torino – offre un ritratto del lato più debole dell’universo violento. Ed è stata ora pubblicata su Physical Review Letters

Edu INAF - Risorse e iniziative per la scuola e la società dell'INAF

Go to top

We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

I accept cookies from this site.

EU Cookie Directive Module Information