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.
Results
Showing 1 to 20 of 50 for “"late-type"”.
-
Chemodynamical Properties of Simulated Late-type Galaxies
… aspects of the galactic chemical evolution of late-type galaxies - both disc-like and dwarf - using a suite of cosmological hydrodynamical simulations, which incorporate the nucleosynthetic pollution of the interstellar medium, supplemented with classical analytical models of Local Group …
-
Zeeman-Doppler Imaging of active late-type stars
Stellare Magnetfelder spielen eine wichtige Rolle bei der Entstehung und Entwicklung von Sternen. Leider entziehen sie sich aber, aufgrund ihrer großen Entfernung zur Erde, einer direkten Beobachtung. Dies gilt zumindest für derzeitige und in naher Zukunft zur Verfügung stehende Instrumente. Um …
-
Deep HI observations of nearby late-type galaxies
… of the low column density neutral hydrogen in late-type nearby mostly isolated galaxies and in the nearby M81 group. Using the KAT-7, GBT and MeerKAT AR1 telescopes, we present in the second chapter a survey of the Hi in a sample of twenty nearby, mostly isolated galaxies down to low column …
-
Deep HI observations of nearby late-type galaxies
… of the low column density neutral hydrogen in late-type nearby mostly isolated galaxies and in the nearby M81 group. Using the KAT-7, GBT and MeerKAT AR1 telescopes, we present in the second chapter a survey of the Hi in a sample of twenty nearby, mostly isolated galaxies down to low column …
-
The Chemical and Dynamical Evolution of Simulated Late-Type Galaxies
… to study the dynamics and chemodynamics of simulated Milky Way analogues. Specifically, I investigate chemical abundances in the solar-neighbourhood and of the outflow rates of gas of Milky Way analogue discs. In the first project, I describe a galaxy simulated with the code RAMSES-CH and …
-
Spot activity of late-type stars : a study of II Pegasi and DI Piscium
… the kinematic mean-field models of different types can lead to a satisfactory reproduction of the solar cycle main properties. These two prevailing dynamo paradigms are briefly introduced in this thesis, as well as their current challenges. For II Peg our time series covers both states of high …
-
Generation and propagation of longitudinal tube waves in late-type stellar atmospheres and the rotation-emission activity relation
… the turbulent medium of the convection zones of late-type stars were computed. Solar magnetic flux tubes of different filling factors were heated with adiabatic and radiatively damped LTW. It was found that the tube geometry plays an important role for heating the outer layers. The response of …
-
Observational and theoretical studies of SiO maser polarization toward late-type evolved stars: Insights from EVPA reversal features
… for the polarization of SiO masers toward late-type evolved stars continue to be a subject of debate. Possible primary sources include the local magnetic field or anisotropic pumping, while additional polarization may arise due to conversion from linear to circular modes through scattering …
-
The chemistry of metal-containing molecules in the circumstellar envelopes of late-type stars: Millimeter-wave observations and abundance modeling
An intensive observational program of Asymptotic Giant Branch (AGB) and post-AGB stars has been conducted in order to investigate the role of metal-containing compounds in the circumstellar envelopes surrounding these objects. The role of metal bearing molecules in the chemical evolution of these …
-
Mapping the interstellar magnetic field: Observations of the Goldreich-Kylafis effect towards late-type evolved stars and star-forming regions
… picture of circumstellar magnetic fields in both late-type evolved stars and star-forming regions. Observations of linearly polarized molecular line transitions arising from the Goldreich-Kylafis (G-K) effect provide valuable insight into the magnetic field geometry in these sources. Through …
-
The Disk Structure of Late Type Galaxies: Determining the Black Hole Mass Function of Low Surface Brightness Galaxies Through Logarithmic Spiral Arm Pitch Angle Measurement
… pertains to the geometric structure of late type (spiral) galaxies, specifically on the relation between the logarithmic spiral pitch angle of the galactic spiral arms with other properties of the galaxy, such as central Supermassive Black Hole (SMBH) mass. Our work continues a study of …
-
The Physical Nature of The Symbiotic Stars
… best if they are binaries consisting of a late-type giant and a hot component which ionizes a gaseous nebula.
-
N(th)-Order Correlation Functions of Galaxies From the Sloan Digital Sky Survey
… The measured o N(theta) are used to calculate the projected, s N, and real space, SN, hierarchical amplitudes. I have used SDSS DR3 data to show that the measurements are robust against the systematic effects of reddening and seeing, and to determine that large differences exist in the …
-
Massive stars in the Galactic Center Quintuplet cluster
… of 1.95 to 2.45\,$\mu$m, containing 85 early-type (OB) stars, 62 late-type (KM) stars, and 13 Wolf-Rayet stars. About 100 of these stars are cataloged for the first time. The main part of the thesis project was concentrated on the analysis of the WR stars of the nitrogen sequence and one …
-
Planets around cool stars: a spectroscopic and photometric study of M dwarfs and their planets
… those orbiting in the habitable zone of Solar-type stars. However, studying M dwarfs is difficult due to their intrinsic faintness and poorly established stellar parameters (radius, metallicity, etc.). For this dissertation I have worked to mitigate these problems with the goals of finding new …
-
Bulges and Disks in the Nearby Universe: Applications to Evolution and Formation of Galaxies
… most luminous tail. Neither the early- nor the late-type relations are pure power laws: both show significant curvature, which we quantify. This curvature confirms that two mass scales are special for both early- and late-type galaxies: M_star ~ 3 x 10^10 and 2 x 10^11 M_sun. The intrinsic …
-
Evolution of Galaxies - Star Formation Histories in Nearby Spheroids
… investigation into the formation of spheroidal type galaxies. The investigation began with modelling studies of early-type galaxies and spiral bulges (SBs). From galaxy formation modelling studies led by experiments with a sample galaxy, some results were obtained; nonsolar abundance ratios in …
-
Measurements and implications of the SDSS DR7 galaxy angular power spectrum
We calculate the angular power spectrum of galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) by using a quadratic estimation method with KL-compression. The primary data sample includes over 18 million galaxies covering more than 5,700 square degrees after masking …
-
Made-to-measure Modelling of Nuclear Star Clusters
The nuclear star clusters of late-type spiral galaxies are comprised of multiple components. Gemini near-infrared spectroscopy of the nuclear star cluster in NGC 4244 shows clear rotation. Earlier, De Lorenzi et al. (2013) constructed two component (disc + spheroid) axisymmetric three integral …
-
Insights from spectral stacking on the Hi content of cluster galaxies in various environments: a tale of two clusters
… H i deficient than field galaxies of the same type. Unlike the Coma cluster, Abell 2626 has not been as well studied, and so little is known about this cluster and its environs. In the second part of the thesis, I present new radio and optical observations of the cluster. Abell 2626 was …
Page 1 of 3