Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 41 for “"globular clusters"”.
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Masses of globular clusters
… velocity dispersions have been derived for 10 globular clusters from high dispersion (6.7A mm-1) coude spectra of the integrated light. Two methods were used. The first involved the comparison of the cluster spectra with star spectra convolved with an appropriate velocity distribution function. …
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Masses of globular clusters
… velocity dispersions have been derived for 10 globular clusters from high dispersion (6.7A mm-1) coude spectra of the integrated light. Two methods were used. The first involved the comparison of the cluster spectra with star spectra convolved with an appropriate velocity distribution function. …
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Precision CCD photometry of globular clusters
… of colour-magnitude photometry of Galactic globular clusters. A survey has been made of recently-published colourmagnitude photometry of globular clusters, and a self-consistent distance scale established for these data, using the method of subdwarf matching to the observed main sequences. …
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A search for fast pulsars in globular clusters
… The extreme stellar densities in the core of globular clusters creates numerous accreting neutron star systems through exchange interactions; this leads to the formation of MSPs in larger numbers than in the galactic disk. Over the course of this project, we have collected over 17 TB of data …
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Dynamical evolution of rotating globular clusters with embedded black holes
… of self-gravitating dense stellar systems (e.g. globular clusters, galactic nuclei) with embedded black holes is investigated, motivated by observational evidences of the existence of central dark objects in these systems. The interaction between the stellar and black hole component is followed …
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A panchromatic study of stellar populations in Galactic Globular Clusters
… Stars (BSS) radial distribution is in stellar clusters and (ii) which are the physical processes that can produce this bimodality. We discuss possible relations between the properties of the BSS radial distribution and the dynamical state of the hosting clusters by making use of dynamical …
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Accreted Globular Clusters in External Galaxies: Why Adaptive Dynamics won’t work
… a well-determined gravitational potential. Globular clusters (GCs) surrounding galaxies can be used as dynamical tracers of the luminous and dark matter distribution at large (kpc) scales. This M.Sc. project investigates - by means of the Auriga galaxy simulations and in anticipation of …
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A spectroscopic and photometric study of MSP companions in Galactic Globular Clusters
… companions of Millisecond Pulsars in Galactic Globular Clusters (GCs) as a part of a large project started at the Department of Astronomy of the Bologna University, in collaboration with other institutions (Astronomical Observatory of Cagliari and Bologna, University of Virginia), specifically …
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Crowded field spectroscopy and the search for intermediate-mass black holes in globular clusters
Globular clusters are dense and massive star clusters that are an integral part of any major galaxy. Careful studies of their stars, a single cluster may contain several millions of them, have revealed that the ages of many globular clusters are comparable to the age of the Universe. These …
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A multiwavelength analysis of M31's globular clusters and their low mass X-ray binaries
A multiwavelength analysis of M31’s globular clusters and their low mass X-ray binaries by Mark B. Peacock Globular clusters (GCs) are dense groups of thousands to millions of stars. They are often very old systems with ages similar to those of their host galaxies and the early Universe. These …
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Search and characterization of pulsars in southern globular clusters: new methodologies and results from an S-band survey
… thesis explores the search for radio pulsars in globular clusters and the development of computational methods to enhance their detection under challenging observational conditions. Pulsars are rapidly rotating neutron stars---remnants of supernova explosions---and represent some of the most …
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Very old and very young compact objects : X-ray studies of galactic globular clusters and recent core-collapse supernovae
… of research, namely, X-ray studies of Galactic globular clusters and X-ray studies of recent core collapse supernovae. My analyses of the Chandra X-ray Observatory observations of the globular clusters NGC 6752 and NGC 6440 revealed as many low-luminosity X-ray sources as was in the entire …
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Constraining the Origin of Multiple Stellar Populations in Stellar Clusters
Globular clusters were among the first luminous objects to form in the Universe. They are dense collections of hundreds of thousands of stars. Globular cluster formation is a major unsolved problem in astrophysics. A new constraint on the problem came from the discovery of unexpected star-to-star …
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Monte-Carlo simulations of globular cluster dynamics
… for the dynamical evolution of dense globular star clusters. Our new study was motivated in part by the wealth of new data made available from the latest optical, radio, and X-ray observations of globular clusters by various satellites and ground-based observatories, and in part by …
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A self contamination model for the formation of globular star clusters
This thesis describes a model of globular cluster formation which allows the self contamination of the cluster by an earlier generation of massive stars. It is first shown that such self-contamination naturally produces an [Fe/H] in the range from -2.5 to -1.0, precisely the same range observed in …
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A self-contamination model for the formation of globular star clusters
This thesis describes a model of globular cluster formation which allows the self contamination of the cluster by an earlier generation of massive stars. It is first shown that such self-contamination naturally produces an (Fe/H) in the range from $-$2.5 to $-$1.0, precisely the same range observed …
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Effects of convection and non-equilibrium radiation transfer in stellar atmospheres /
… the atmospheres of stars that belong to Galactic globular clusters 47 Tuc and NGC 6752 shows that NLTE effects have significantly larger impact on the formation of O and Na spectral lines than the effects related to convection do. Finally, we determine 3D + NLTE abundances of Li, O, Na, and Ba in …
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Dynamics and evolution of dense stellar systems
… and evolution of dense stellar systems such as globular clusters. First, I present the results of a study of mass segregation in two-component star clusters, based on a large number of numerical N-body simulations using our Monte-Carlo code. Heavy objects, which could represent stellar remnants …
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Galactic Archaeology with Gaia
… potential extragalactic origin of the Milky Way globular clusters based on their dynamics and various other information such as age, metallicity, horizontal branch index. It reveals a collection of globular clusters with extragalactic origin, originating from the "Gaia Sausage". Chapter 7 is a …
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Fokker-Planck models and globular cluster evolution
Numerical models for globular cluster evolution using the orbit-averaged Fokker-Planck equation are compared with observations of the globular clusters M71 and NGC 6397. The first set of models studied includes a mass spectrum, a tidal boundary and allows for a central energy source from the …
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