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Showing 1 to 20 of 33 for “"Metallicities"”.
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Morphology and metallicities of OTELO galaxies.
In this thesis we explore the OTELO (OSIRIS Tunable Filter Emission Line Object) survey. OTELO is a very deep, pencil beam survey for the search of emission line sources by means of the tunable filters of the OSIRIS instrument, installed at the Gran Telescopio Canarias. A tomography scan method …
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Metallicities and stellar populations in spiral bulges
A major aim of current astrophysical research is the development of models of galaxy formation that are consistent with observational data. Until recently, the main tools of such research were broadband colours. However, the Lick system of indices has recently provided researchers with a more …
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Kinematics of Nearby Subdwarfs And the Luminosity Function of the Galactic Thick Disk
… motions were combined with radial velocities and metallicities from CLLA. The kinematical behavior is discussed in particular in relation to their metallicities. For stars with metallicity -1.0<[Fe/H]<-0.4, the velocity distribution represent the thick disk population. We derived the luminosity …
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The Rise and Fall of Star-Forming Clumps: Formation and Evolution of the Building Blocks of Galaxies Across Cosmic Time
… the Gemini-North telescope, we measure gas-phase metallicities for a small sample (<30) of clumpy and nonclumpy galaxies. We find that clumpy galaxies exhibit systematically lower metallicities relative to the mass–metallicity relation, consistent with clump formation driven by gas inflow. The …
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Kinematics and stellar populations of the galactic bulge.
… radial and/or rotation velocities and obtain metallicities for the stellar population of the Galactic bulge, several hundred spectra of giants have been obtained. These include three bulge fields at projected distances from the Galactic center of 1.5, 1.7 and 1.7 kpc, and 33 globular and open …
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Probing the history of galaxy clusters with metallicity and entropy measurements
… In the centers of clusters, we find that the metallicities of high-mass clusters are much less dispersed than those of low-mass clusters. A comparison of metallicity with the regularity of the X-ray emission morphology suggests that metallicities in low-mass clusters are more susceptible to …
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High-resolution spectroscopy of very active solar-type stars
… to determine Lithium abundances and metallicities. Although two of these stars may be close binaries, it is likely that eleven are single stars or wide binaries, of which four seem to be Pleiades age and two others appear Hyades age. It is usually expected that young stars are to be …
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Planets around cool stars: a spectroscopic and photometric study of M dwarfs and their planets
… improve on techniques to measure M dwarf metallicities. Using wide binaries with a Solar-type primary and an M dwarf companion as calibrator stars, I perform an unbiased search for metal-sensitive features in visible and near-infrared spectra. This yields a list of spectral lines (or …
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The chemical evolution of galaxies explored through multi-object integral field spectroscopy
… of a population of galaxies with low metallicities that have enhanced N/O abundances. I show that the galaxies with the highest N/O values also have higher stellar masses and star formation rates. I then investigate the possibility that these galaxies have undergone recent gas …
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Chemical and kinematical evolution in nearby dwarf spheroidal galaxies
… On the other hand, I found a wide spread in the metallicities, reaching from -3 dex to near-solar. Hence, I could show that age and metallicity conspire to produce old, metal poor stars at the same locus on the RGB as young, metal rich ones. This manifestation of an age-metallicity degeneracy …
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Population Synthesis Models for IMF studies
… evolutionary phases. The PSMs cover a range of metallicities with [Fe/H]= 0, –1.31 and –1.81 for scaled-solar and _-enhanced metal mixtures. The models were used to study the behaviour of the IMF indices defined in the literature and the results are in good agreement with what other PSMs have …
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The structure of the Large Magellanic Cloud
… abundances. Measuring the distribution of metallicities of RR Lyrae stars in a galaxy gives one clues to the origin of galaxies. It is known that the pulsation periods of RR Lyraes is broadly correlated with their metallicity. This fact has been used for investigating the metallicity …
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The structure of the large magellanic cloud
… abundances. Measuring the distribution of metallicities of RR Lyrae stars in a galaxy gives one clues to the origin of galaxies. It is known that the pulsation periods of RR Lyraes is broadly correlated with their metallicity. This fact has been used for investigating the metallicity …
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Massive stars in low metallicity environments
… the evolution of massive stars for a range of metallicities, including our Milky Way galaxy and the Magellanic Clouds. This work provides an insight into the evolutionary models conducted in an endeavour to understand the dominant physical processes acting on massive stars, chapters 3 and 4. …
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The creation and use of a chemical kinetics code to model and understand the atmospheres of hot Jupiters
… Levi to run a suite of models across a range of metallicities to produce the abundance of a number of molecules in any hot Jupiter's atmosphere. Our parameter sweep covers metallicities between 0.1x and 10x solar values for the C/H, O/H and N/H ratios, and equilibrium temperatures of hot Jupiters …
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Effects of convection and non-equilibrium radiation transfer in stellar atmospheres /
… of C, O, Si, Ti, Fe, and Ni is largest at lowest metallicities, both in the atmospheres of TO and RGB stars: the differences in the abundaces predicted by the 3D hydrodynamical and 1D hydrostatic stellar model atmospheres may reach to –1.1 and –0.8 dex in the TO and RGB stars, respectively. The …
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Intergalactic baryon enrichment and implications for galaxy evolution at high redshift
… systems (such as LLSs) is consistent with lower metallicities and lower ionization states in the circumgalactic medium than is seen at later times.
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A New Library of Stellar Model Atmospheres and Spectra
… the Asplund et al (2009) abundances for several metallicities ranging from -2.5 to +0.5, and these have been used to produce new grids of ATLAS9 model atmospheres and synthetic spectra for stars with effective temperatures of 3500 K to 100000 K and log g from 0.0 dex to 0.5 dex, for both normal …
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Gravitational collapse, compact objects and gravitational waves in General Relativity and modified gravity
… plausible range of stellar progenitor masses and metallicities, as well as a large part of the parameter space of this class of modified theories of gravity. Next we test the robustness of our results by expanding the simulations to ST theories with self-interacting potentials. Finally, we study …
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Understanding massive disk galaxy formation through resolved stellar populations
… Red Giant Branch (RGB) can be used to determine metallicities of old stellar populations that have only shallow photometry. Based on the largest sample of globular clusters ever used for such studies, we quantify the relation between metallicity and color in the widely used HST ACS filters F606W …
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