1,721,190 research outputs found
Evolutionary population synthesis and the Magellanic Clouds clusters
No full textSynthetic bolometric luminosities and U, B, V fluxes are computed for models of globular clusters using available stellar evolutionary tracks for two chemical compositions and for a large interval of age. The author presents some results and considerations relative to the study of some characteristics of the Magellanic Clouds globular clusters
PRACE: Partnership for Advanced Computing in Europe
No full textRoberto Capuzzo-Dolcetta è stato nominato membro dell'Access Committee di PRACE (Partnership for Advanced Computing in Europe), progetto europeo che unisce le piu' importanti infrastrutture di calcolo TIER0 per uso scientifico in Europa
Some comments about computational astrophysics in Italy
No full textModern science is becoming more and more dependent on the use of computers. Actually, there is a new paradigm other than the classical two of experimental and theoretical science: computational science, that is the one which makes use of powerful computer facilities to perform simulations of those complex systems that cannot be fully theoretically modeled neither fully experimentally checked. We are all aware of the great success of high performance computational science in the understanding of the human genoma, for instance. In the field of astronomoy and astrophysics, high performance computing has already met applications of overwhelming importance. It is one of the field of major development, in an international context. In this brief introduction to the Meeting I express some opinions on the state of the art of computational astrophysics in our national scientific community
ISCRA: Italian SuperComputing Resource Allocation ISCRA
No full textR. Capuzzo Dolcetta è membro del "board of referees" per l'assegnazione di tempo di calcolo sulle piattaforme di calcolo del CINECA nell'ISCRA project
Visiting professorship
No full textTeaching (undergraduate course A323 Extragalactic Astronomy) and scientific collaboration with prof. P. Hodge and G. lake.Leave authorized by Sapienza
Decaying globular cluster systems and galactic nuclear activity
No full textGlobular cluster are systems that evolve dissipatively in non symmetric galactic potentials, losing energy and angular momentum. As a consequence, the GCS radial profile in a galaxy evolves significantly, so to differ from the one of the collisionless stellar bulge phase: this can explain the observations, which indicate how the GCS distribution in galaxies is usually more extended than the underlining stellar distribution. Moreover, the GCS orbital decay implies that a significant quantity of mass is carried toward the mother galaxy's central galactic region in a time scale short compared to the Hubble time. We show that this mass can accrete a galactic nucleus and fuel its activity in early stages of galactic life
Super star cluster formation via globular cluster merging
No full textI testi delle presentazioni sono pubblicati on-line sul sito http://www.mpia-hd.mpg.de/NC08
Galactic nuclear activity induced by globular cluster merging
No full textThe interpretation of the difference observed between the radial distribution of globular clusters and that of halo-bulge stars in elliptical galaxies is discussed in terms of evolution of their globular cluster systems. I present a short summary of the evidence that dynamical evolution of globular cluster systems is not only able to explain the flattening of their distribution toward the galactic center, but also it may have played an important role on the primordial activity of the parent galaxy.
Conferenza su invito. E.Grebel and K.Brander eds
Elliptical galaxy nuclei activity powered by infalling globular clusters
No full textGlobular Cluster systems evolve, in galaxies, due to internal and external dynamics and tidal phenomena. One of the causes of evolution, dynamical friction, is responsible for the orbital decay of massive clusters into the innermost galactic regions. It is found that these clusters are effective source of matter to feed a central galactic black hole such to make it grow and shine as an AGN
The evolution of the globular cluster system in a triaxial galaxy: Can a galactic nucleus form by globular cluster capture?
No full textAmong the possible phenomena inducing evolution of the globular cluster system in an elliptical galaxy, dynamical friction due to field stars and tidal disruption caused by a central nucleus is of crucial importance. The aim of this paper is the study of the evolution of the globular cluster system in a triaxial galaxy in the presence of these phenomena. In particular, the possibility is examined that some galactic nuclei have been formed by frictionally decayed globular clusters moving in a triaxial potential. We find that the initial rapid growth of the nucleus, due mainly to massive clusters on box orbits falling in a short time scale into the galactic center, is later slowed by tidal disruption induced by the nucleus itself on less massive clusters in the way described by Ostriker, Binney, and Saha. The efficiency of dynamical friction is such to carry to the center of the galaxy enough globular cluster mass available to form a compact nucleus, but the actual modes and results of cluster-cluster encounters in the central potential well are complicated phenomena which remains to be investigated. The mass of the resulting nucleus is determined by the mutual feedback of the described processes, together with the initial spatial, velocity, and mass distributions of the globular cluster family. The effect on the system mass function is studied, showing the development of a low- and high-mass turnover even with an initially flat mass function. Moreover, in this paper is discussed the possibility that the globular cluster fall to the galactic center has been a cause of primordial violent galactic activity. An application of the model to M31 is presented
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