Galaxy Dynamics in Clustered Environments download PDF, EPUB, Kindle
Galaxy Dynamics in Clustered Environments download PDF, EPUB, Kindle
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Author: Maria J R R Pereira
Number of Pages: 158 pages
Published Date: 01 Sep 2011
Publisher: Proquest, Umi Dissertation Publishing
Publication Country: Charleston SC, United States
Language: English
ISBN: 9781243703651
File size: 32 Mb
File Name: Galaxy.Dynamics.in.Clustered.Environments.pdf
Download Link: Galaxy Dynamics in Clustered Environments
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Galaxy orientations have been studied statistically for over 70 years now, but it is only recently that alignments have been found on scales larger than those of close interacting pairs. Large scale alignments between galaxies and their surrounding tidal fields are expected to occur during formation, but what happens when these galaxies fall into larger systems? Can their orientations tell us anything about the accretion process itself? In this dissertation I will focus on the radial alignment of satellite galaxies, in which a satellite's long axis points preferentially toward the center of its host. I present observational evidence for this type of galaxy alignment in the SDSS DR3 using a sample of X-ray selected massive clusters. Then, using results from N-body cosmological simulations, I will argue that this effect is the result of a secular tidal interaction between the galaxies and their host potential. The analysis shows that subhalos are effectively torqued by their host throughout their orbits, so that their major axes tend to be aligned with the gradient of the host potential. The significant discrepancy between the magnitude of the effect as seen in these simulations and that detected in observations motivates the work of the next chapter, where I perform numerical experiments on idealized, high resolution N-body models of elliptical galaxies. These experiments show that the more centrally concentrated luminous components of galaxies take longer to react to the external torque, and, in the particular case of mildly eccentric orbits, their orientations can figure rotate in periodic patterns that are not radially aligned on average. The mechanism is more effective on galaxies that have larger triaxialities, but the overall effect of torquing is to make galaxies rounder, since radially misaligned galaxies tend to become more spherical as they are torqued towards equilibrium. In the last chapter, I briefly discuss the impact of these results for galaxy modeling, strong and weak lensing surveys, and the dynamics of disk galaxies in clusters. I then present a potentially useful application of this result, which proposes to use galaxy orientations in order to find the centers of optically selected clusters.
Read online Galaxy Dynamics in Clustered Environments Buy Galaxy Dynamics in Clustered Environments Download Galaxy Dynamics in Clustered Environments ebook, pdf, djvu, epub, mobi, fb2, zip, rar, torrent Download to iPad/iPhone/iOS, B&N nook Galaxy Dynamics in Clustered Environments
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Galaxy Dynamics in Clustered Environments by Maria J R R Pereira
Author: Maria J R R Pereira
Number of Pages: 158 pages
Published Date: 01 Sep 2011
Publisher: Proquest, Umi Dissertation Publishing
Publication Country: Charleston SC, United States
Language: English
ISBN: 9781243703651
File size: 32 Mb
File Name: Galaxy.Dynamics.in.Clustered.Environments.pdf
Download Link: Galaxy Dynamics in Clustered Environments
---------------------------------------------------------------
Galaxy orientations have been studied statistically for over 70 years now, but it is only recently that alignments have been found on scales larger than those of close interacting pairs. Large scale alignments between galaxies and their surrounding tidal fields are expected to occur during formation, but what happens when these galaxies fall into larger systems? Can their orientations tell us anything about the accretion process itself? In this dissertation I will focus on the radial alignment of satellite galaxies, in which a satellite's long axis points preferentially toward the center of its host. I present observational evidence for this type of galaxy alignment in the SDSS DR3 using a sample of X-ray selected massive clusters. Then, using results from N-body cosmological simulations, I will argue that this effect is the result of a secular tidal interaction between the galaxies and their host potential. The analysis shows that subhalos are effectively torqued by their host throughout their orbits, so that their major axes tend to be aligned with the gradient of the host potential. The significant discrepancy between the magnitude of the effect as seen in these simulations and that detected in observations motivates the work of the next chapter, where I perform numerical experiments on idealized, high resolution N-body models of elliptical galaxies. These experiments show that the more centrally concentrated luminous components of galaxies take longer to react to the external torque, and, in the particular case of mildly eccentric orbits, their orientations can figure rotate in periodic patterns that are not radially aligned on average. The mechanism is more effective on galaxies that have larger triaxialities, but the overall effect of torquing is to make galaxies rounder, since radially misaligned galaxies tend to become more spherical as they are torqued towards equilibrium. In the last chapter, I briefly discuss the impact of these results for galaxy modeling, strong and weak lensing surveys, and the dynamics of disk galaxies in clusters. I then present a potentially useful application of this result, which proposes to use galaxy orientations in order to find the centers of optically selected clusters.
Read online Galaxy Dynamics in Clustered Environments Buy Galaxy Dynamics in Clustered Environments Download Galaxy Dynamics in Clustered Environments ebook, pdf, djvu, epub, mobi, fb2, zip, rar, torrent Download to iPad/iPhone/iOS, B&N nook Galaxy Dynamics in Clustered Environments
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