The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

A MODEST review

We present an account of the state of the art in the fields explored by the research community invested in 'Modeling and Observing DEnse STellar systems'. For this purpose, we take as a basis the activities of the MODEST-17 conference, which was held at Charles University, Prague, in September 2017. Reviewed topics include recent advances in fundamental stellar dynamics, numerical methods for the solution of the gravitational N-body problem, formation and evolution of young and old star clusters and galactic nuclei, their elusive stellar populations, planetary systems, and exotic compact objects, with timely attention to black holes of different classes of mass and their role as sources of gravitational waves. Such a breadth of topics reflects the growing role played by collisional stellar dynamics in numerous areas of modern astrophysics. Indeed, in the next decade, many revolutionary instruments will enable the derivation of positions and velocities of individual stars in the Milky Way and its satellites and will detect signals from a range of astrophysical sources in different portions of the electromagnetic and gravitational spectrum, with an unprecedented sensitivity. On the one hand, this wealth of data will allow us to address a number of long-standing open questions in star cluster studies; on the other hand, many unexpected properties of these systems will come to light, stimulating further progress of our understanding of their formation and evolution.Comment: 42 pages; accepted for publication in 'Computational Astrophysics and Cosmology'. We are much grateful to the organisers of the MODEST-17 conference (Charles University, Prague, September 2017). We acknowledge the input provided by all MODEST-17 participants, and, more generally, by the members of the MODEST communit

Caratterizzazione archeometrica e diffusione in Liguria della ceramica a cobalto e manganese

Le ceramiche smaltate e decorate a cobalto e manganese rinvenute in Liguria trovano precisi confronti con il materiale edito e l'ampia bibliografia di riferimento . Queste ceramiche sono dunque ben tipologizzate e rappresentano un preciso indicatore cronologico per le stratigrafie liguri comprese tra l’ultimo quarto del XII secolo e la metà del secolo successivo. In questa sede è stata affrontata una sintesi a livello regionale sul materiale rinvenuto negli scavi editi; in particolare, l’attenzione si è soffermata sull’esame del contesto genovese di Palazzo Ducale. La ceramica a cobalto e manganese è stata inoltre indagata dal punto di vista archeometrico, utilizzando i metodi della microscopia ottica ed elettronica . Lo studio in sezione sottile ha riguardato un totale di diciannove campioni rappresentativi della classe ceramica, provenienti da scavi di Pisa, Genova e Marsiglia (v. la tabella allegata per i riferimenti archeologici e bibliografici). Otto sono stati analizzati per la prima volta ; mentre gli altri undici, facenti parte della banca dati dell'Istituto di Storia della Cultura Materiale (ISCUM) di Genova, sono stati già pubblicati da T. Mannoni negli anni settanta e ottanta . Tre campioni di Palazzo Ducale sono stati quindi scelti per un più approfondito studio tessiturale e composizionale dei rivestimenti, svolto al microscopio elettronico a scansione (SEM) e alla microsonda elettronica

Antimicrobial and antiviral activity of xylosyl methylthio adenosine, a naturally occurring analogue of methylthio adenosine from Doris verrucosa

Xylosyl-methylthio-adenosine, a naturally occurring analogue of 5'-deoxy-5'-methylthio-adenosine, has been postulated to play a protective role during egg development in the mollusc Doris verrucosa. However, in vitro tests showed that this analogue is devoid of activity against fungi, bacteria and viruses

Structure and absolute stereochemistry of syphonoside, a unique macrocyclic glycoterpenoid from marine organisms

(Figure Presented) The glycoterpenoid syphonoside (1) is the main secondary metabolite of both the marine mollusk Syphonota geographica and the sea-grass Halophila stipulacea, two Indo-Pacific species migrated to the Mediterranean Sea through the Suez Canal. The structure and the absolute stereochemistry of 1, which displays unique structural features, has been accomplished by using a combination of spectroscopic techniques, degradation reactions, and conformational analysis methods. Compound 1 was able to inhibit high density induced apoptosis in a number of human and murine carcinoma cell lines. © 2007 American Chemical Society

La ceramica a Taches Noires albisolese e la sua distribuzione nel mercato coloniale. Un caso di studio archeometrico da Haiti

status: publishe