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1
PANOZZO, SIMONE. "THE SPECTRAL HALO." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/657582.
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In this thesis, we construct a function defined over the space of integral overconvergent modular forms of Andreatta, Iovita and Pilloni, taking values in the module of continuous functions from p adic integers to a suitably constructed perfection of an overconvergence region of the formal weight space. The existence of this function is related to the possibility of proving Coleman's Halo conjecture about the distribution of eigenvalues of the Hecke operator at p acting on spaces of overconvergent modular forms. In the thesis, we construct the function, and we also compute explicitly the action of the operator over those continuous functions which are in the image of the map. Moreover, in chapter 3, we also show that the space of such continuous functions admits a Mahler basis.
2
Arnold, Richard A. "The galactic stellar halo." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386335.
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O'Meara, Jeffrey A. "Dynamic kinetic resolution: Diastereoselective amination of alpha-halo esters and alpha-halo imidazolidinones." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/9493.
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The synthesis of optically active N-protected $\alpha$-amino esters and $\alpha$-amino imidazolidinones via a dynamic kinetic resolution protocol will be discussed. The methodology is based on fundamental reactivity differences between diastereomeric $\alpha$-halo esters and $\alpha$-halo imidazolidinones. The process involves nucleophillic displacement of the diastereomeric $\alpha$-halogenated esters and imidazolidinones with benzylamine. The corresponding displacement products are obtained with 70 - $>$ 98% de. Both absolute configurations are possible at the aminated postion by appropriate choice of the chiral auxiliary. The application of this methodology towards the synthesis of several optically active $\alpha$-amino esters was investigated. A five step sequence, starting from commercially available acid chlorides, was developed for synthesizing $\alpha$-amino esters in $\sim$40% overall yield. By utilizing dibenzylamine as the nucleophile, the DKR process has been effectively utilized in an approach to Reetz aldehydes ($\alpha$-dibenzylamino aldehydes). The increased bulk of dibenzylamine provides increased diastereoselectivity relative to benzylamine and the Reetz aldehyde precursors are obtained with a high degree of optical purity. Mechanistic aspects the reaction will also be discussed.
4
Daw, Edward John 1969. "A search for halo axions." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50335.
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Jiang, Lilian. "Cosmological halo formation and mergers." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/11004/.
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My research has centred around establishing the nature of dark matter haloes by investigating their abundance as a function of halo mass, the formation his- tory of each halo, commonly called the merger tree, and the internal structure of the halo, in terms of their radial density profiles and angular momentum. In the first part of this thesis, I present a new algorithm which groups the subhaloes found in cosmological N-body simulations by structure finders such as subfind into dark matter haloes whose formation histories are strictly hier- archical. One advantage of these ‘Dhaloes’ over the commonly used friends-of- friends (FoF) haloes is that they retain their individual identity in cases when FoF haloes are artificially merged by tenuous bridges of particles or by an over- lap of their outer diffuse haloes. Dhaloes are thus well suited for modelling galaxy formation and their merger trees form the basis of the Durham semi- analytic galaxy formation model, galform. Applying the Dhalo construction to the ΛCDM Millennium-2 simulation we find that approximately 90% of Dhaloes have a one-to-one, bijective match with a corresponding FoF halo. The remaining 10% are typically secondary components of large FoF haloes. Although the mass functions of both types of haloes are similar, the mass of Dhaloes correlates much more tightly with the virial mass, M200, than FoF masses. Approximately 80% of FoF and bijective and non-bijective Dhaloes are relaxed according to standard criteria. For these relaxed haloes all three types have similar concentration– M200 relations and, at fixed mass, the concentration distributions are described accurately by log-normal distributions. In the second part of this thesis, I present distributions of orbital parameters of infalling satellite haloes at the time of crossing the virial radius of their host halo. Detailed investigation of the orbits is crucial as it represents the initial conditions which determine the later evolution of the substructure within the host. I use merger trees in a high resolution cosmological N-body simulation to trace the satellite haloes and measure their orbits when they first infall into the host halo. I find that there is a trend of the orbital parameters with the ratio between the satellite halo mass and the host halo mass at infall. I find that the more massive satellites move along more eccentric orbits with lower specific angular momentum than less massive satellites. I also search for possible correlations between different orbital parameters and provide accurate fitting formulae for the two independent orbital parameters (the total velocity and the radial-to-total velocity ratio). Using combinations of these formulae, we successfully fit all the other orbital parameters.
6
McCaine, Gina. "Halo orbit design and optimization." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FMcCaine.pdf.
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Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, March 2004.Thesis advisor(s): I. Michael Ross, Don Danielson. Includes bibliographical references (p. 39-40). Also available online.
7
Totten, Edward James. "Carbon stars in the Galactic Halo." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263490.
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Vale, António Manuel Dias de Sousa. "Linking halo mass to galaxy luminosity." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614222.
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Fermani, Francesco. "Modelling the Milky Way stellar halo." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:bcd70530-506d-46c2-8c99-7f5b8f08f915.
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We motivate the importance of understanding the kinematics and dynamics of the Milky Way stellar halo both in unravelling the formation history and evolution of our host Galaxy and in the more general context of galaxy dynamics. We present a cleaned picture of the kinematics of the smooth component of the stellar halo: we develop a method to quantify the average distance error on a sample of stars based on the idea of Schoenrich et al. (2012), but adapted so that it uses velocity information only on average. We use this scheme to construct an analytic distance calibration for Blue Horizontal Branch (BHB) field halo stars in Sloan colours and demonstrate that our calibration is a) more accurate than the ones available and b) unbiased w.r.t. metallicity and colour. We measure the rotation of the smooth component of the stellar halo with a tool-set of four estimators that use either only the l.o.s. velocities or the full 3D motion. From two samples of BHB stars from the Sloan Digital Sky Survey, we favour a non-rotating single halo. We critique conflicting results in the literature based on similar samples and trace back the disagreement (either in the sign of rotation or in the morphology of the halo) to sample contaminations and/or neglect account of the halo geometry. We propose a scheme that generalizes any isotropic spherical model to a model where the potential is axisymmetric and the distribution function is a function of the three actions. The idea is to approximate the Hamiltonian as a function of the actions with a library of quadratic fits to surfaces of constant energy in action space and then make explicit the dependence of the energy on the three actions in the ergodic distribution function. The transparency of the physics implied by the model we achieve, should make it possible to combine our spheroidal models to the f(J)-models of Binney (2010) for the disks and of Pontzen & Governato (2013) for the dark-matter halo, and obtain a complete actions-defined dynamical model of the Milky Way Galaxy.
10
Werner, Kim Fiona [Verfasser]. "Halo bias renormalisation / Kim Fiona Werner." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1218301570/34.
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Martin, Susan Morag. "The ontology of the Venetian halo in its Italian context." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3311.
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This thesis aims to reposition the halo’s status within an artwork through arguing a reassessment of its activity 'as a sign' rather than acceptance of its passivity. This active state is further explored and expanded by a heuristic application of semiotic theory to interrogate its fluctuation between sign/non-sign and its oscillation between a seemingly real status and behaviour juxtaposed with its very consciously artificial “manifestation”. A variety of halo shapes are considered, together with texture contained in and on its surface, and this has revealed the Venetian and Venetan artistic innovation of “glass” and “silk” haloes, through artists’ utilisation of contemporaneous industrial practices and their application to halo appearance. Additionally, extant architectural vocabulary is translated and reformulated into internal halo motifs by Venetian and Venetan artists, further enhancing the halo’s somatic characteristics, contextualized by examination of halo representation in various media in Florence, Rome and Siena, and a consideration of haloes within other, mainly Italian, centres. Additionally, the fugitive and transient qualities of the nimbus are noted, with its mimesis of the dying corporeal body in its fading insubstantiality, a further factor in its inexorably reductive form as increasing realism in art challenges its ontological traits. Textual characters contained within the halo body are also examined in their many forms and languages and their contribution to an intertextual function espoused by the ideologeme. An adjunct to this function is the halo’s propagandist role presented by artists. It will be demonstrated how all these different strands of interpretation are imbricated in the changing theological, political and societal landscape, encapsulated within the halo.
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Gerigk, Frank. "Beam halo in high-intensity hadron linacs." [S.l.] : [s.n.], 2006. http://opus.kobv.de/tuberlin/volltexte/2007/1466.
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Tinker, Jeremy L. "Constraining cosmology with the Halo occupation distribution." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1120663291.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xviii, 319 p.; also includes graphics. Includes bibliographical references (p. 310-319). Available online via OhioLINK's ETD Center
14
Konz, Christian. "Dynamische Stabilisierung von Hochgeschwindigkeitswolken im galaktischen Halo." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-10072.
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Gerén, Linda. "Pionic Fusion Study of the 6He Halo." Doctoral thesis, Stockholms universitet, Fysikum, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1356.
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The structure of the halo nucleus 6He has been investigated in a pionic fusion experiment at the CELSIUS storage ring facility in Uppsala. The 4He(d, 6He)π+ reaction was studied 0.6 - 5.0 MeV above threshold in the centre-of-mass frame with a deuteron beam incident on a 4He gas target. The 6He ions were detected in a ΔE - E solid-state detector telescope inserted into the CELSIUS ring. The results for the total and differential cross section are presented and compared to results for the analogue reaction producing the 3.56 MeV analogue state in 6Li. A simple model of the reaction gives results consistent with earlier findings of 6He as having a spatial extent considerably exceeding that of the alpha particle. It is also shown that information about the high momentum part of the halo wave function can be extracted from the results of this pionic fusion measurement.
16
Henderson, Steven G. D. "Spectroscopic studies of platinum halo-phosphine complexes." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/28226.
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Gill, Stuart P. D., and na. "The evolution of a dark halo substructure." Swinburne University of Technology, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20061009.115152.
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In this dissertation we analyse the dark matter substructure dynamics within a
series of high-resolution cosmological galaxy clusters simulations generated with the
N-body code MLAPM.
Two new halo finding algorithms were designed to aid in this analysis. The
first of these was the 'MLAPM-halo-nder' (MHF), built upon the adaptive grid structure
of MLAPM. The second was the 'MLAPM-halo-tracker' (MHT), an extension of MHF
which allowed the tracking of orbital characteristics of gravitationally bound objects
through any given cosmological N-body-simulation. Using these codes we followed
the time evolution of hundreds of satellite galaxies within the simulated clusters.
These clusters were chosen to sample a variety of formation histories, ages, and
triaxialities; despite their obvious differences, we and striking similarities within
the associated substructure populations. Namely, the radial distribution of these
substructure satellites follows a 'universal' radial distribution irrespective of the
host halo's environment and formation history. Further, this universal substructure
profile is anti-biased with respect to the underlying dark matter profile. All satellite
orbits follow nearly the same eccentricity distribution with a correlation between
eccentricity and pericentre. The destruction rate of the substructure population is
nearly independent of the mass, age, and triaxiality of the host halo. There are,
however, subtle differences in the velocity anisotropy of the satellite distribution.
We nd that the local velocity bias at all radii is greater than unity for all halos
and this increases as we move closer to the halo centre, where it varies from 1.1 to
1.4. For the global velocity bias we nd a small but slightly positive bias, although
when we restrict the global velocity bias calculation to satellites that have had at
least one orbit, the bias is essentially removed.
Following this general analysis we focused on three specific questions regarding
the evolution of substructures within dark matter halos.
Observations of the Virgo and Coma clusters have shown that their galaxies align with the principal axis of the cluster. Further, a recent statistical analysis of some
300 Abell clusters conrm this alignment, linking it to the dynamical state of the
cluster. Within our simulations the apocentres of the satellite orbits are preferentially
found within a cone of opening angle 40 degrees around the major axis of the host
halo, in accordance with the observed anisotropy found in galaxy clusters. We do,
however, note that a link to the dynamical age of the cluster is not well established.
Further analysis connects this distribution to the infall pattern of satellites along
the filaments, rather than some 'dynamical selection' during their life within the
host's virial radius.
We then focused our attention on the outskirts of clusters investigating the socalled
'backsplash population', i.e. satellite galaxies that once were inside the virial
radius of the host but now reside beyond it. We and that this population is significant in number and needs to be appreciated when interpreting empirical galaxy
morphology-environmental relationships and decoupling the degeneracy between nature
and nurture. Specifically, we and that approximately half of the galaxies with
current clustercentric distance in the interval 1- 2 virial radii of the host are backsplash
galaxies which once penetrated deep into the cluster potential, with 90% of
these entering to within 50% of the virial radius. These galaxies have undergone
significant tidal disruption, losing on average 40% of their mass. This results in a
mass function for the backsplash population different to those galaxies infalling for
the first time. We further show that these two populations are kinematically distinct
and should be observable spectroscopically.
Finally we present a detailed study of the real and integrals-of-motion space
distributions of a disrupting satellite obtained from one of our self-consistent highresolution
cosmological simulations. The satellite has been re-simulated using various
analytical halo potentials and we and that its debris appears as a coherent
structure in integrals-of-motion space in all models ('live' and analytical potential)
although the distribution is significantly smeared for the live host halo. The primary
mechanism for the dispersion is the mass growth of the host. However, when
quantitatively comparing the effects of 'live' and time-varying host potentials we
conclude that not all of the dispersion can be accounted for by the steady growth
of the host's mass. We ascribe the remaining differences to additional effects in the
'live' halo such as non-sphericity of the host and interactions with other satellites,
which have not been modelled analytically.
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Holland, Stephen. "The globular clusters an halo of M31." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0029/NQ27163.pdf.
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Gerén, Linda. "Pionic Fusion Study of the ⁶He Halo /." Stockholm : Physics Department, Stockholm university, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1356.
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Gill, Stuart P. D. "The evolution of a dark halo substructure." Australasian Digital Thesis Program, 2005. http://adt.lib.swin.edu.au/public/adt-VSWT20061009.115152/index.html.
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Thesis (Ph.D) - Swinburne University of Technology, [Faculty of Information & Communication Technologies], 2005.A dissertation presented in total fulfillment of the requirements of for the degree of Doctor of Philosophy, [Faculty of Information and Communication Technologies], Swinburne University of Technology, 2005. Typescript. Bibliography p. 145-154.
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Talamas, Sean N. "Perceptions of intelligence and the attractiveness halo." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/10851.
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Perceptions of intelligence are strongly related to attractiveness and have a significant impact on first impressions. The introductory chapters (1 - 3) provide an overview of the literature on attractiveness, halo effects, and intelligence, while the experimental chapters (4 - 6) explore perceptions of cues to intelligence beyond attractiveness, individual differences in the susceptibility to the halo, and the accuracy of perceptions of competence. Chapter 4 investigated the malleable facial cues of eyelid-openness and mouth curvature and their influence on perceived intelligence. Attractiveness partially mediated intelligence impression, but effects of eyelid-openness and subtle smiling enhanced intelligence ratings independent of attractiveness. These effects were observed and replicated in between individual (cross-sectional) studies of natural images of adult faces, child faces, through digital manipulation of individual cues in the same faces, and in a within individual sleep-restricted sample. Chapter 5 investigated the relationship between perceived intelligence and attractiveness by exploring whether a raters' own intelligence may be related to a stronger endorsement of the perceived intelligence-attractiveness halo. The correlation between ratings of the perceived intelligence and attractiveness was found to be stronger for participants who scored higher on an intelligence test than participants with lower intelligence test scores. Chapter 6 investigated the limiting effects of attractiveness on perceptions of competence. When statistically controlling for the attractiveness halo, academic performance could be predicted from judgments of conscientiousness but not from ratings of intelligence. Thus this thesis demonstrates that malleable facial cues can influence perceptions of intelligence independent of attractiveness, identifies an individual difference that influences endorsement of the intelligence-attractiveness halo, and shows the limiting effects of the attractiveness halo on potentially accurate perceptions of academic performance. Collectively these findings provide evidence of the powerful influence of attractiveness on perceptions of intelligence; such work is necessary if we are to mitigate such bias.
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Niederste-Ostholt, Jens Martin. "Building blocks of the galactic stellar halo." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609117.
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Felipe, Gislaine de. "Transferência orbitais envolvendo órbitas do tipo halo." Instituto Nacional de Pesquisas Espaciais, 2004. http://urlib.net/sid.inpe.br/jeferson/2005/07.14.18.30.
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Nas atividades espaciais, é de grande importância o estudo das trajetórias que os veículos espaciais devem seguir para completar uma missão. No presente trabalho, estudam-se as manobras orbitais envolvendo órbitas Halo para vários sistemas de primários. Para realizar este estudo utiliza-se o método de Lindstedt-Poincaré para a determinação das órbitas e o método de Lambert para as transferências envolvidas, tanto para as transferências com tempo livre como para as manobras de rendez-vous. Para exemplificar as técnicas desenvolvidas uma missão completa no sistema Terra-Lua envolvendo o problema restrito de três corpos é calculada em detalhes. Ainda estudam-se neste trabalho as mesmas manobras para o problema restrito bi-circular de quatro corpos. A seguir, um modelo propulsado de swing-by é desenvolvido e a sua eficiência em transferir um veiculo entre uma órbita de estacionamento em tomo da Terra até uma órbita Halo no sistema Terra-Sol utilizando um swing-by coma Lua é medida.In space activities, it is of great importance the study of trajectories that the space vehicles should follow to complete a mission. In the present work, maneuvers involving Halo orbits for several systems of primary are studied. To accomplish this study the method of Lindstedt-Poincaré is used for the etermination of the orbits and the method of Lambert is used for the transfers involved in both cases for the transfers with free time for the rendez-vous maneuvers. To exemplify the techniques developed here a complete mission in the Earth-Moon system involving the restricted three bodies problem is calculated in details. It is still studied in this work the same maneuvers for the restricted bi-circular problem of four bodies. To proceed, a propelled model for the swing-by is studied and its efficiency in transfering a spacecraft from a parking orbit around the Earth to a Halo orbit in the Earth-Sun system using a swing-by with the Moon is measured.
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Marasco, Antonino <1984>. "The gaseous halo of the Milky Way." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5210/1/marasco_antonino_tesi.pdf.
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In the last decade, sensitive observations have revealed that disc galaxies are surrounded by multiphase gaseous halos produced by the circulation of gas from the discs to the environment and vice-versa.
This Thesis is a study of the gaseous halo of the Milky Way carried out via the modelling of the HI emission and the available absorption-line data. We fitted simple kinematical models to the HI LAB Survey and found that the Galaxy has a massive (~3x10^8 Mo) HI halo extending a few kiloparsecs above the plane. This layer rotates more slowly than the disc and shows a global inflow motion, a kinematics similar to that observed in the HI halos of nearby galaxies.
We built a dynamical model of the galactic fountain to reproduce the properties of this layer. In this model, fountain clouds are ejected from the disc by SN feedback and - as suggested by hydrodynamical simulations - triggers the cooling of coronal gas, which is entrained by the cloud wakes and accretes onto the disc when the clouds fall back. For a proper choice of the parameters, the model reproduces well the HI data and predicts an accretion of coronal gas onto the disc at a rate of 2 Mo/yr.
We extended this model to the warm-hot component of the halo, showing that most of the ion absorption features observed towards background sources are consistent with being produced in the turbulent wakes that lag behind the fountain clouds. Specifically, the column densities, positions, and velocities of the absorbers are well reproduced by our model.
Finally, we studied the gas content of galaxies extracted from a cosmological N-body+SPH simulation, and found that an HI halo with the forementioned properties is not observed, probably due ti the relatively low resolution of the simulations.
25
Marasco, Antonino <1984>. "The gaseous halo of the Milky Way." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5210/.
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In the last decade, sensitive observations have revealed that disc galaxies are surrounded by multiphase gaseous halos produced by the circulation of gas from the discs to the environment and vice-versa.
This Thesis is a study of the gaseous halo of the Milky Way carried out via the modelling of the HI emission and the available absorption-line data. We fitted simple kinematical models to the HI LAB Survey and found that the Galaxy has a massive (~3x10^8 Mo) HI halo extending a few kiloparsecs above the plane. This layer rotates more slowly than the disc and shows a global inflow motion, a kinematics similar to that observed in the HI halos of nearby galaxies.
We built a dynamical model of the galactic fountain to reproduce the properties of this layer. In this model, fountain clouds are ejected from the disc by SN feedback and - as suggested by hydrodynamical simulations - triggers the cooling of coronal gas, which is entrained by the cloud wakes and accretes onto the disc when the clouds fall back. For a proper choice of the parameters, the model reproduces well the HI data and predicts an accretion of coronal gas onto the disc at a rate of 2 Mo/yr.
We extended this model to the warm-hot component of the halo, showing that most of the ion absorption features observed towards background sources are consistent with being produced in the turbulent wakes that lag behind the fountain clouds. Specifically, the column densities, positions, and velocities of the absorbers are well reproduced by our model.
Finally, we studied the gas content of galaxies extracted from a cosmological N-body+SPH simulation, and found that an HI halo with the forementioned properties is not observed, probably due ti the relatively low resolution of the simulations.
26
Jofré, Pfeil Paula. "The age of the milky way halo stars." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-133404.
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Sturino, Claudio F. "Samarium (II) iodide cyclizations of halo- and carbonylhydrazones." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10324.
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The preparation of a variety of halo and keto C=N containing systems for use in free radical cyclization is described. The 6-exo radical cyclization of bromo oxazolines (A) was first examined under standard tin hydride conditions, but only reduction products were isolated. The use of syringe pump techniques also gave only the reduced product. The use of Bu$\sb3$SnD demonstrated that a 1,5-hydrogen shift was responsible for the premature quenching of the alkyl radical. A related bromo-oxazoline was prepared which was not capable of undergoing a 1,5-hydrogen shift after generation of the radical was prepared, but it did not cyclize under any conditions employed. Thus attention was directed towards hydrazones (B), whose reactivity in radical cyclizations has received little attention. This study has shown that simple bromo-hydrazones underwent an extremely efficient radical cyclization to give high yields of the cyclopentyl and cyclohexyl hydrazines (C). Ketyl radicals were generated from the corresponding aldehydes and ketones (D) using SmI$\sb2$/HMPA and their intramolecular cyclizations onto hydrazones was shown to be a facile and high yielding process. Unlike the alkyl radical cyclizations, the ketyl radical reactions were more selective at higher temperatures. Thus at room temperature, the 5-exo ketyl radical cyclization gave $>$15:1 selectivity in favour of the isomer with the hydroxy and hydrazino groups trans (E). The difference between the ketyl and alkyl cyclizations is even more notable in the 6-exo cyclizations. These reactions gave generally modest selectivities in the alkyl series but the 6-exo ketyl radical cyclizations were highly selective at all temperatures examined. The products of these reactions, cyclic $\beta$-hydroxy hydrazines, are closely related to an important class of natural products, $\beta$-hydroxy amines. Thus methods for cleaving the N-N bond to yield the corresponding amines were examined. Having developed conditions for cleavage of the N-N bond, the utility of the method was demonstrated in a brief synthesis of a penta-substituted $\beta$-hydrazino alcohol which is related to the allosimizoline class of antifungal and insecticidal agents. L-Xylose was used as the starting material for the preparation of the chiral hydrazone-aldehyde. In the second portion of this thesis, we describe the determination of the rate constant for the 5 and 6 exo cyclizations of alkyl radicals using radical clock techniques. Thus a halo-hydrazone (F) was prepared that contained an alkene suitably positioned for a 5-exo hexenyl-type cyclization. The corresponding 5-exo hydrazone cyclization was surprisingly too fast to be measured with the 5-hexenyl clock. The rate constant for this fast reaction could be determined by running the cyclization in concentrated Bu$\sb3$SnH and measuring the amounts of cyclized vs. reduced products. This intermolecular clock gave a rate constant for the 5-exo cyclization of k$\sb{\rm cis}$ = 1.1 $\times$ 10$\sp8$s$\sp{-1}$ and k$\sb{\rm trans}$ = 4.6 $\times$ 10$\sp7$s$\sp{-1}$ at 80$\sp\circ$C, which is approximately 200 times faster than the corresponding alkene cyclization. From this data we calculated that a cyclization run in neat Bu$\sb3$SnH at 80$\sp\circ$C would give a 12:1 ratio of products in favour of the cyclized product. A related system (G) was prepared to test the 5 and 6 exo ketyl radical cyclizations. As in the simple alkyl radical systems, the hydrazone proved to be a more efficient radical acceptor than the corresponding alkene. (Abstract shortened by UMI.)(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)
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Thom, Christopher, and na. "High velocity clouds and the Milky Way Halo." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20060920.101419.
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This thesis presents an exploration of stars and gas in the halo of our Galaxy. A sample
of 8321 field horizontal branch (FHB) stars was selected from the Hamburg/ESO Survey.
The stars make excellent tracers of the Milky Way halo, and we studied the kinematics
of a subset of the HES FHB stars, comparing their velocity dispersions to those predicted
by several models. Since these stars are intrinsically luminous, hot and numerous they
make ideal probes of the distances to high-velocity clouds (HVCs) - clouds of neutral
hydrogen gas whose distances are largely unknown and which do not fit simple models
of Galaxy rotation. A catalogue of stars which align with the HVCs was developed. High
resolution spectroscopy of 16 such HVC probes with the Magellan telescope has yielded
a remarkably tight distance constraint to complex WB. This is one of only a handful of
such distance limits so far established. Lower distance limits were set for several other
clouds. Finally, we have suggested that some of the HVCs may be associated with the
accretion onto the MilkyWay of the Sagittarius dwarf galaxy.
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Thom, Christopher. "High velocity clouds and the Milky Way Halo." Australasian Digital Theses Program, 2006. http://adt.lib.swin.edu.au/public/adt-VSWT20060920.101419/index.html.
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Thesis (PhD) - Swinburne University of Technology, 2006.A dissertation presented in fulfillment of the requirements for the degree of Doctor of Philosophy, Swinburne University of Technology - 2006. Typescript. Bibliography: p. 83-91.
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Brimioulle, Fabrice. "Dark matter halo properties from galaxy-galaxy lensing." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-159994.
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Die Forschungsergebnisse der letzten Jahre haben gezeigt, dass das Universum bei weitem nicht nur aus baryonischer Materie besteht. Tatsächlich scheinen 72% aus sogenannter Dunkler Energie zu bestehen, während selbst vom verbleibenden Teil nur etwa ein Fünftel baryonischer Materie zugeordnet werden kann. Der Rest besteht aus Dunkler Materie, deren Beschaffenheit bis heute nicht mit Sicherheit geklärt ist. Ursprünglich in den Rotationskurven von Spiralgalaxien beobachtet, wurde die Notwendigkeit ihrer Existenz inzwischen auch in elliptischen Galaxien und Galaxienhaufen nachgewiesen. Tatsächlich scheint Dunkle Materie eine entscheidende Rolle in der Strukturbildung im Universum gespielt zu haben. In der Frühzeit des Universums, als die Materieverteilung im Weltraum noch äußerst gleichmäßig war und nur sehr geringe Inhomogenitäten aufwies, bildeten sie die Kondensationskeime für den gravitativen Kollaps der Materie. Numerische Simulationen haben gezeigt, dass der heute beobachtbare Entwicklungszustand des Universums erst durch die zusätzliche Masse Dunkler Materie ermöglicht wurde, die den strukturellen Kollaps erheblich beschleunigte und nur dadurch zur heute beobachtbaren Komplexität der Strukturen führen konnte. Da Dunkle Materie nicht elektromagnetisch wechselwirkt, sondern sich nur durch ihre Schwerkraft bemerkbar macht, stellt der Gravitationslinseneffekt eine ausgezeichnete Methode dar, die Existenz und Menge an Dunkler Materie nachzuweisen. Der schwache Gravitationslinseneffekt macht sich zu Nutzen, dass die intrinsischen Orientierungen der Galaxien im Weltraum keine Vorzugsrichtung haben, gleichbedeutend mit ihrer statistischen Gleichverteilung. Die gravitationsbedingte kohärente Verzerrung der Hintergrundobjekte führt zu einer Abweichung von dieser Gleichverteilung, die von den Eigenschaften der Gravitationslinsen abhängt und daher zu deren Analyse genutzt werden kann.
Diese Dissertation beschreibt die Galaxy-Galaxy-Lensing-Analyse von insgesamt 89 deg^2 optischer Daten, die im Rahmen des CFHTLS-WIDE-Surveys beobachtet wurden und aus denen im Rahmen dieser Arbeit photometrische Rotverschiebungs- und Elliptizitätskataloge erzeugt wurden. Das Galaxiensample besteht aus insgesamt 5×10^6 Linsen mit Rotverschiebungen von 0.05 < z_phot ≤ 1 und einem zugehörigen Hintergrund von insgesamt 1.7×10^6 Quellen mit erfolgreich gemessenen Elliptizitäten in einem Rotverschiebungsintervall von 0.05 < z_phot ≤ 2. Unter Annahme analytischer Galaxienhaloprofile wurden für die Galaxien die Masse, das Masse-zu-Leuchtkraft-Verhältnis und die entsprechenden Halomodellprofilparameter sowie ihre Skalenrelationen bezüglich der absoluten Leuchtkraft untersucht. Dies geschah sowohl für das gesamte Linsensample als auch für Linsensamples in Abhängigkeit des SED-Typs und der Umgebungsdichte. Die ermittelten Skalenrelationen wurden genutzt, um die durchschnittlichen Werte für die Galaxienhaloparameter und eine mittlere Masse für die Galaxien in Abhängigkeit ihres SED-Typs zu bestimmen. Es ergibt sich eine Gesamtmasse von M_total = 23.2+2.8−2.5×10^11 h^{−1} M_⊙ für eine durchschnittliche Galaxie mit einer Referenzleuchtkraft von L∗ = 1.6×10^10 h^{−2} L_⊙. Die Gesamtmasse roter Galaxien bei gleicher Leuchtkraft überschreitet diejenige des entsprechenden gemischten Samples um ca. 130%, während die mittlere Masse einer blauen Galaxie ca. 65% unterhalb des Durchschnitts liegt. Die Gesamtmasse der Galaxien steigt stark mit der Umgebungsdichte an, betrachtet man die Geschwindigkeitsdispersion ist dies jedoch nicht der Fall. Dies bedeutet, dass die zentrale Galaxienmateriedichte kaum von der Umgebung sondern fast nur von der Leuchtkraft abhängt. Die Belastbarkeit der Ergebnisse wurde von zu diesem Zweck erzeugten Simulationen bestätigt. Es hat sich dabei gezeigt, dass der Effekt mehrfacher gravitativer Ablenkung an verschiedenen Galaxien angemessen berücksichtigt werden muss, um systematische Abweichungen zu vermeiden.The scientific results over the past years have shown that the Universe is by far not only composed of baryonic matter. In fact the major energy content of 72% of the Universe appears to be represented by so-called dark energy, while even from the remaining components only about one fifth is of baryonic origin, whereas 80% have to be attributed to dark matter. Originally appearing in observations of spiral galaxy rotation curves, the need for dark matter has also been verified investigating elliptical galaxies and galaxy clusters. In fact, it appears that dark matter played a major role during structure formation in the early Universe. Shortly after the Big Bang, when the matter distribution was almost homogeneous, initially very small inhomogeneities in the matter distribution formed the seeds for the gravitational collapse of the matter structures. Numerical n-body simulations, for instance, clearly indicate that the presently observable evolutionary state and complexity of the matter structure in the Universe would not have been possible without dark matter, which significantly accelerated the structure collapse due to its gravitational interaction. As dark matter does not interact electromagnetically and therefore is non-luminous but only interacts gravitationally, the gravitational lens effect provides an excellent opportunity for its detection and estimation of its amount. Weak gravitational lensing is a technique that makes use of the random orientation of the intrinsic galaxy ellipticities and thus their uniform distribution. Gravitational tidal forces introduce a coherent distortion of the background object shapes, leading to a deviation from the uniform distribution which depends on the lens galaxy properties and therefore can be used to study them. This thesis describes the galaxy-galaxy lensing analysis of 89 deg^2 of optical data, observed within the CFHTLS-WIDE survey. In the framework of this thesis the data were used in order to create photometric redshift and galaxy shape catalogs. The complete galaxy sample consists of a total number of 5×10^6 lens galaxies within a redshift range of 0.05 < z_phot ≤ 1 and 1.7×10^6 corresponding source galaxies with redshifts of 0.05 < z_phot ≤ 2 and successfully extracted shapes. Assuming that the galaxy halos can be described by analytic profiles, the scaling relations with absolute luminosity for the galaxy masses, their mass-to-light ratios and the corresponding halo parameters have been extracted. Based on the obtained scaling relations, the average values for the corresponding halo parameters and the mean galaxy masses for a given luminosity were derived as a function of considered halo model, the galaxy SED and the local environment density. We obtain a total mass of M_total = 23.2+2.8−2.5 ×10^11 h{−1} M_⊙ for an average galaxy with chosen reference luminosity of L∗ = 1.6×10^10 h{−2} L_⊙. In contrast, the mean total masses for red galaxies of same luminosity exceed the value of the average galaxy about 130%, while the mass of a blue galaxy is about 65% below the value of an average fiducial galaxy. Investigating the influence of the environmental density on the galaxy properties we observe a significant increase of the total integrated masses with galaxy density, however the velocity dispersions are not affected. This indicates that the central galaxy matter density mostly depends on the galaxy luminosity but not on the environment. Simulations based on the extracted scientific results were built, verifying the robustness of the scientific results. They give a clear hint that multiple deflections on different lens galaxies have to be properly accounted for in order to avoid systematically biased results.
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Hagen, Philipp [Verfasser]. "Effective Field Theory for Halo Nuclei / Philipp Hagen." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/104861610X/34.
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Lynn, Stuart. "Simulating large cosmology surveys with calibrated halo models." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5682.
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In this thesis I present a novel method for constructing large scale mock galaxy and halo catalogues and apply this model to a number of important topics in modern cosmology. Traditionally such mocks are created through first evolving a high resolution particle simulation from a set of initial conditions to the present epoch, identifying bound structures and their evolution, and finally applying a semi-analytic prescription for galaxy formation. In contrast to this computationally expensive procedure, I use low resolution simulations to obtain a density field that traces large scale modes. From this background I sample the population statistics of halos: the number of halos which are typically found within a region of a given overdensity, to produce a halo catalogue. From the halo catalogue I then produce galaxies by appealing to the halo model. In this model the expected number of galaxies within a halo and the distribution of their properties is dependent on halo mass alone. By sampling conditional luminosity functions for a number of populations of galaxies, I produce a galaxy catalogue with luminosity and colour properties. The aim of developing algorithm is not to probe the mechanics of galaxy formation in great detail. It is instead intended as a method of rapidly producing mock galaxy and halo catalogues rapidly on modern desktop computers. The approach we will take is to try to distill the minimal algorithm required to achieve this and still provide useful catalogues for observational cosmologists. Both the conditional mass function and conditional luminosity functions required for the algorithm are calibrated from the Millennium Simulation, one of the highest resolution cosmology simulations to date, and its associated semi-analytic catalogues. In Chapter 2 I examine these statistics and provide fits to the quantities of interest. As a test of the method, in Chapter 3 I produce a halo and galaxy catalogue from the same large scale modes as the Millennium Simulation. The clustering statistics of galaxies and halos within this re-simulation are calculated and compared with those of the original. Con dent of the accuracy of the method, in Chapter 4 I populate a number of simulations, each 8 times the volume of the Millennium Simulation, and study the evolution of the Baryon Acoustic Oscillation signal. For each population (dark matter, halos and galaxies) I fit the BAO in the power spectrum to obtain the shift in the BAO peak. In Chapter 5 I extend the algorithm to produce lightcones: simulated skies in which the evolution of the Universe along the line of sight is accounted for. I simulate the geometry and limitations of a major pending survey and calculate the expected clustering signature I expect to see in both. The redshift space distortions induced by peculiar velocities of galaxies along the line of sight are determined and their ability to distinguish between gravity models is also explored. In Chapter 6 I detail a further extension to the algorithm for simulating weak gravitational lensing surveys. I use the analytic 2D surface density pro files of NFW profiles to dress each dark matter halo on a lightcone. The sum of these pro files over the entire population can be used to construct high resolution maps of the convergence. From these maps I calculate the spectrum of the convergence and compare with theoretical predictions. Finally in Chapter 7 I discuss further possible applications and extensions of the algorithm I have developed in this thesis.
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Ryans, Robert Samuel Isaac. "Stars and interstellar gas in the galactic halo." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388179.
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Ford, Alison. "Lithium in young open clusters and halo stars." Thesis, Keele University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391218.
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Yu, D. B. (Daniel Byungyoon) 1976. "An improved RF cavity search for halo axions." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29459.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (leaves 165-167) and index.
The axion is a hypothetical elementary particle and cold dark matter candidate. In this RF cavity experiment, halo axions entering a resonant cavity immersed in a static magnetic field convert into microwave photons, with the resulting photons detected by a low-noise receiver. I present new limits on the axion-to-photon coupling and local axion dark matter halo mass density from a RF cavity axion search in the axion mass range 1.9-2.3 [mu]eV, broadening the search range to 1.9-3.3 [mu]eV. In addition, I report first results from an improved analysis technique, which improves the experiment sensitivity by 13%.
by D.B. Yu.
Ph.D.
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Ma, Zhao M. Eng Massachusetts Institute of Technology. "HALO : re-forming architectural space with light caustics." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111701.
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Thesis: M. Arch., Massachusetts Institute of Technology, Department of Architecture, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (page 115).
What form can light take? Light has been an eternal theme in architectural design. Light defines, shapes, and transforms space in various ways. However, the way light has been used in human history has not changed: the variation of space is a result of the interaction between light and shadow along with the geometry and materials that defines the space itself. Through the BLOCKING of light comes the variation of shadows. Is it possible to extend the possibility of light from a basic level? This thesis questions one of the fundamental uses of light in architectural space: how can we use light beyond the realm of shuttering? With the implementation of a set of state-of-the-art algorithms in computer graphics field, the thesis presents a serious of explorations in how refraction can re-form the architectural experience using the movement of light in both still and dynamic ways. Through the REDISTRIBUTION of light comes the variation of time.
by Zhao Ma.
M. Arch.
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Lovell, Mark Richard. "Halo substructure and the nature of dark matter." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/8461/.
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The ΛCDM paradigm has been very successful at predicting the properties of the large scale (> 10Mpc) Universe, but has recently struggled to explain phenomena observed on small scales, such as the central densities, abundances, and orbital configurations of satellite galaxies. This emergence of tension between observations and theory has co- incided with CERN measurements that disfavour the simplest supersymmetric models, which provide some of the most popular cold dark matter candidate particles. One pos- sible solution to some of these problems is that the dark matter may instead be made up of sterile neutrinos: these particles would have masses of 1-10keV and behave as ’warm’ dark matter (WDM), with consequences for the formation of galaxies. In this thesis we use high resolution simulations of Milky Way-analogue dark matter haloes to examine the role of filaments on satellite orbits and WDM on satellite abundance and structure. We find in the former case that dark matter filaments can funnel subhaloes into cor- related orbits and so ease the tension with observations. We also find that WDM is a possible solution to the problem of satellite galaxy densities, since structure formation is delayed in WDM and thus the centres of haloes form when the density of the Universe is lower. In order to generate the required number of satellite galaxies, we find that the WDM thermal-equivalent particle mass > 1.6keV. In addition to the work on satellite galaxies, we use a series of gas-hydrodynamic simulations of our Milky Way-analogue halo to examine the process of reionisation in WDM. We find that the suppression of small scale structure in the 1.4keV WDM model prevents the simulated L∗ galaxy, along with its satellites, from reionising its own local volume quickly enough to satisfy the reionisation redshift constraint set by the recent Planck satellite results, in contrast to CDM.
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Hess, Fiona Millicent. "Halo- and organogold(I) complexes as potential metallomesogens." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/9757.
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Includes bibliography.There is currently much interest in how the properties of liquid crystals may be altered by metal atoms. Gold(I) complexes of the type RAuL have recently been shown to exhibit interesting liquid crystal behaviour. As molecular structure and intermolecular forces play a major role in liquid crystal chemistry, changing the nature of the R and L groups result in changes mesomorphic properties. The aim of the project was to synthesise RAuL complexes with stilbazole ligands and to investigate how different R groups influence the liquid crystal properties. ClAu(n-OST) complexes, n-OST = trans-4,4'-alkoxystilbazole with n = number of carbon atoms in the alkoxy chain, were synthesised from ClAu(tht) and n-OST. They were found to exhibit smectic A mesophases, melting between 135-153 °C and decomposing at the clearing point at 168-180 °C. The transition temperatures decreased as the chain length of the n-OST ligand increased.
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Caldwell, Nelson, Matthew G. Walker, Mario Mateo, Edward W. Olszewski, Sergey Koposov, Vasily Belokurov, Gabriel Torrealba, Alex Geringer-Sameth, and Christian I. Johnson. "Crater 2: An Extremely Cold Dark Matter Halo." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623952.
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We present results from MMT/Hectochelle spectroscopy of 390 red giant candidate stars along the line of sight to the recently discovered Galactic satellite Crater 2. Modeling the joint distribution of stellar positions, velocities, and metallicities as a mixture of Crater 2 and Galactic foreground populations, we identify similar to 62 members of Crater 2, for which we resolve a line-of-sight velocity dispersion of sigma(nu los) = 2.7(-0.3)(+0.3) km s(-1) and a. mean velocity of
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James, Carol Renée. "Chemical and kinematic correlations in the galactic halo /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Smet, Christophe Olivier. "Asymmetric drift and halo flattening in disk galaxies." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7203/.
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The main result in this work is the solution of the Jeans equations for an axisymmetric galaxy model containing a baryonic component (distributed according to a Miyamoto-Nagai profile) and a dark matter halo (described by the Binney logarithmic potential).
The velocity dispersion, azimuthal velocity and some other interesting quantities such as the asymmetric drift are studied, along with the influence of the model parameters on these (observable) quantities. We also give an estimate for the velocity of the radial flow, caused by the asymmetric drift.
Other than the mathematical beauty that lies in solving a model analytically, the interest of this kind of results can be mainly found in numerical simulations that study the evolution of gas flows. For example, it is important to know how certain parameters such as the shape (oblate, prolate, spherical) of a dark matter halo, or the flattening of the baryonic matter, or the mass ratio between dark and baryonic matter, have an influence on observable quantities such as the velocity dispersion.
In the introductory chapter, we discuss the Jeans equations, which provide information about the velocity dispersion of a system. Next we will consider some dynamical quantities that will be useful in the rest of the work, e.g. the asymmetric drift. In Chapter 2 we discuss in some more detail the family of galaxy models we studied. In Chapter 3 we give the solution of the Jeans equations. Chapter 4 describes and illustrates the behaviour of the velocity dispersion, as a function of the several parameters, along with asymptotic expansions. In Chapter 5 we will investigate the behaviour of certain dynamical quantities for this model. We conclude with a discussion in Chapter 6.
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Niemiec, Anna, Eric Jullo, Marceau Limousin, Carlo Giocoli, Thomas Erben, Hendrik Hildebrant, Jean-Paul Kneib, et al. "Stellar-to-halo mass relation of cluster galaxies." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/625737.
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In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: Assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can be used as a proxy of the infall mass. We study the stellar-to-halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the Dark Energy Survey (DES) science verification archive, the Canada-France-Hawaii Lensing Survey (CFHTLenS) and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we find a stellar-to-halo mass relation in good agreement with the theoretical expectations from Moster et al. for central galaxies. In the centre of the cluster, we find that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this finding as further evidence for tidal stripping of dark matter haloes in high-density environments.
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Marinacci, Federico <1983>. "Dynamics of the halo gas in disc galaxies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3743/1/Marinacci_Federico_tesi.pdf.
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This Thesis studies the dynamics of hot and cold gas outside the plane in galaxies like the Milky-Way (extra-planar gas) and focuses on the interaction between disc and halo material. Stationary models for the cold phase of the
extra-planar gas are presented. They show that the kinematics of this phase must be influenced by the interaction with an ambient medium that we identify as the
hot cosmological corona that surrounds disc galaxies. To study this interaction a novel hydrodynamical code has been implemented and a series of hydrodynamical simulations has been run to investigate the mass and momentum exchange between the cold extra-planar gas clouds and the hot corona. These simulations show that the coronal gas can condense efficiently in the turbulent wakes that form behind the cold clouds and it can be accreted by the disc to sustain star formation. They also predict that the corona cannot be a static structure but it must rotate and
lag by approximately 80-120 km/s with respect to the disc.
Implications of the results of this Thesis for the evolution of star-forming galaxies and for the large-scale dynamics of galactic coronae are also briefly discussed.
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Marinacci, Federico <1983>. "Dynamics of the halo gas in disc galaxies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3743/.
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This Thesis studies the dynamics of hot and cold gas outside the plane in galaxies like the Milky-Way (extra-planar gas) and focuses on the interaction between disc and halo material. Stationary models for the cold phase of the
extra-planar gas are presented. They show that the kinematics of this phase must be influenced by the interaction with an ambient medium that we identify as the
hot cosmological corona that surrounds disc galaxies. To study this interaction a novel hydrodynamical code has been implemented and a series of hydrodynamical simulations has been run to investigate the mass and momentum exchange between the cold extra-planar gas clouds and the hot corona. These simulations show that the coronal gas can condense efficiently in the turbulent wakes that form behind the cold clouds and it can be accreted by the disc to sustain star formation. They also predict that the corona cannot be a static structure but it must rotate and
lag by approximately 80-120 km/s with respect to the disc.
Implications of the results of this Thesis for the evolution of star-forming galaxies and for the large-scale dynamics of galactic coronae are also briefly discussed.
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Kleinheinrich, Martina. "Dark matter halos of galaxies studied with weak gravitational lensing." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968817351.
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Hetznecker, Helmut. "Die Entstehungsgeschichte der dichten Kerne von CDM-Halos." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96199245X.
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Martins, Jéssica Silvano. "O modelo de halos e o espectro de potência da matéria escura morna /." São Paulo, 2015. http://hdl.handle.net/11449/154698.
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Orientador: Rogério RosenfeldCo-orientador: Flávia Sobreira
Banca: José Geraldo Pereira
Banca: Marcos Vinicius Borges Teixeira Lima
Resumo: Neste trabalho revisaremos o formalismo do Modelo de Halos e suas aplicações. No Modelo de Halos, toda a matéria do universo está contida em objetos virializados de matéria escura, resultado de colapso gravitacional. A distribuição de matéria escura nesses halos e como eles estão distribuídos no universo são os principais elementos para caracterizá-los. Mostraremos a teoria que descreve o modelo de halos e testaremos sua eficácia comparando-a com simulações numéricas de formação de estrutura no universo, por meio do espectro de potência. Faremos também uma adaptação do modelo de halos para a matéria escura morna e mostraremos como esse tipo de matéria suprime a formação de estrutura do universo em pequenas escalas
Abstract: In this work we review the formalism of the Halo Model, and its applications. In the Halo Model all the matter of the universe is contained in virialized dark matter halos, as a result of gravitational collapse. The distribution of dark matter within these halos, and how they are distributed in the universe are the main features to caracterize them. We'll show the theory that describes the Halo Model and test is efficiency by comparing it to numerical simulations of structure formation in the universe, using the power spectrum. We'll also do an adaptation of Halo model to warm dark matter, and show how this type of matter supress the structure formation of the universe in small scales
Mestre
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Martins, Jéssica Silvano [UNESP]. "O modelo de halos e o espectro de potência da matéria escura morna." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/154698.
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Neste trabalho revisaremos o formalismo do Modelo de Halos e suas aplicações. No Modelo de Halos, toda a matéria do universo está contida em objetos virializados de matéria escura, resultado de colapso gravitacional. A distribuição de matéria escura nesses halos e como eles estão distribuídos no universo são os principais elementos para caracterizá-los. Mostraremos a teoria que descreve o modelo de halos e testaremos sua eficácia comparando-a com simulações numéricas de formação de estrutura no universo, por meio do espectro de potência. Faremos também uma adaptação do modelo de halos para a matéria escura morna e mostraremos como esse tipo de matéria suprime a formação de estrutura do universo em pequenas escalas
In this work we review the formalism of the Halo Model, and its applications. In the Halo Model all the matter of the universe is contained in virialized dark matter halos, as a result of gravitational collapse. The distribution of dark matter within these halos, and how they are distributed in the universe are the main features to caracterize them. We'll show the theory that describes the Halo Model and test is efficiency by comparing it to numerical simulations of structure formation in the universe, using the power spectrum. We'll also do an adaptation of Halo model to warm dark matter, and show how this type of matter supress the structure formation of the universe in small scales
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Lin, Huang-De Hennessy. "Low-temperature halo-carbon homoepitaxial growth of 4H-SiC." Diss., Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-10142008-150935.
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梁世民 and Sai-man Leung. "Effect of dark halo on the evolution of galaxies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B3121163X.
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