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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Strong ram-pressure stripping and widespread star formation in the high-velocity system towards the center of the Perseus cluster

Yu, Pui-ling, 余佩玲 January 2015 (has links)
I present spectroscopic imaging of the high-velocity system (HVS) towards the central cD galaxy (NGC 1275) in the Perseus Cluster at a high spectral resolution for the first time. Previous observation suggests that the HVS is a highly inclined dusty and gas-rich galaxy moving towards the center of NGC 1275 at a high speed of 3000 km/s relative to the systemic velocity of NGC 1275 through the hot intracluster medium (ICM). If this is the case, then the HVS should be undergoing intense ram-pressure stripping. However, there is tentative evidence for ram-pressure stripping in the HVS, and furthermore confined to a small region of the galaxy. Previous observations also point out that at the location where the HVS is seen, there are many star clusters seen towards the inner region of NGC 1275. The separation of young star clusters between those belong to NGC 1275 and those belong to the HVS is, however, not clearly defined. The primary scientific objectives are to (i) search for evidence for ram-pressure stripping in the HVS, as well as signs of tidal interactions between the HVS and NGC 1275; and (ii) separate the numerous young star clusters seen towards the entire NGC 1275 into those associated with the HVS and those associated with NGC 1275. NGC 1275 and the HVS were observed simultaneously with the use of Potsdam Multi-Aperture Spectrophotometer. The main emission lines being studied are the Hα & [NII]λ6548,6483 lines in NGC 1275 and the HVS. I present maps of intensity distribution, velocity field and velocity dispersion of the Hαemission of the HVS, as well as the line ratio of the [NII] doublets lines to the Hα line in the HVS. I find that the line ratio of [NII]/Hα is less than 0.1 throughout the entire body of the HVS, indicating metallicity is low in the HVS. I also find that the metallicity is decreasing with distance from the center, just like other normal spiral galaxies. I demonstrate that a large fraction of the young star clusters seen towards the inner regions of NGC 1275 are closely associated with bright Hα-emitting regions in the HVS, and trace the overall Hα-emitting body of the HVS, suggesting that some young star clusters are associated to the HVS. I find that there are two distributions of young star clusters in color-color space, providing a way to separate out the star clusters likely belong to the HVS. I present evidence that the HVS is experiencing intense ram-pressure stripping and also evidence suggesting that the HVS is possibly tidally interacting with NGC 1275. The results demonstrate that the HVS is a dusty, gas-rich, low-metallicity galaxy that has been disrupted by ram-pressure stripping and possibly also tidal interactions. I show that the HVS exhibit widespread and vigorous (~3.6 MM_⊙ yr^(-1)) star formation over the last at least ~0.1 Gyr. The vigorous SFR of the HVS is in contrast to what suggested by the observed low metallicity (suggestive of relatively weak star-formation activity over the recent history). The SFR of the HVS is likely to be triggered by the same process that produces global distortion on the HVS, here ram pressure stripping and possibly tidal interaction are in consideration. / published_or_final_version / Physics / Master / Master of Philosophy
62

La formation initiale des professeurs de musique: la construction d'une identité de musicien-enseignant" English : The initial training of the professors of music: The construction of a musician-teacher identity"/...

Regnard, Françoise 26 September 2007 (has links)
La thèse porte sur la construction d'une identité spécifique chez les professeurs des écoles de musique: musicien et enseignant. La recherche s'intéresse aux personnes musiciennes qui suivent un cursus de formation initiale à l'enseignement musical spécialisé et montre, par l'analyse de différents parcours, comment l'identité de musicien s'articule avec l'identité d'enseignant. In english The thesis relates the construction of specific identity to the professors of the music schools: musicians and teachers. The research task concerns the study of musician people who follow an initial training specialized in musical teaching and shows, by the analysis of various training directions, how the identity of the musician turns around the teacher’s identity.
63

The small-scale structure of molecular clouds

Hobson, Michael Paul January 1993 (has links)
No description available.
64

Aspects of prospective memory

Conlon, Joseph January 1995 (has links)
No description available.
65

Molecular gas in orion-monoceros

Wilson, Bruno Alexander January 2002 (has links)
No description available.
66

The Eikonal approach to reaction-diffusion equations in multiply-connected domains

Mulholland, Anthony J. January 1994 (has links)
No description available.
67

The distribution of low-mass stars in the disc of the galaxy

Kroupa, Pavel January 1992 (has links)
No description available.
68

Dynamical interactions between young stellar objects

Price, Nigel Mark January 1995 (has links)
No description available.
69

The Adamello Complex : Aspects of its emplacement and uplift

McRae, T. A. January 1983 (has links)
No description available.
70

Electromagnetic investigation of the Reykjanes Ridge near 58 ÌŠNorth

MacGregor, Lucy M. January 1997 (has links)
No description available.

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