dc.date.accessioned | 2013-03-12T08:25:58Z | |
dc.date.available | 2013-03-12T08:25:58Z | |
dc.date.issued | 2006 | en_US |
dc.date.submitted | 2006-08-11 | en_US |
dc.identifier.citation | Holhjem, Karianne. The density profile of clusters of galaxies. Masteroppgave, University of Oslo, 2006 | en_US |
dc.identifier.uri | http://hdl.handle.net/10852/10932 | |
dc.description.abstract | Two galaxy clusters, Abell 1351 and Abell 1995, are examined using weak gravitational lensing
techniques. Mass maps are created, and the clusters' density and shear profiles are compared to
theoretical predictions.
Gravitational lensing is important for studying the mass distribution of the Universe. It pro-
vides methods of estimating the masses of everything acting as a gravitational lens, without
making assumptions about the dynamical state and the nature of the gravitating matter. In
particular, this includes the dark matter, which is currently believed to make up for about
90% of the entire matter in the Universe, evading any other means of direct detection.
Dark matter and its gravitation therefore govern the architecture and evolution of the largest
bounds objects known in the Universe, from galaxies up to supercluster of galaxies.
This thesis uses data from the CFH12K wide-field imager at the Canada-France-Hawaii Telescope.
In order to obtain mass estimates for the galaxy clusters by weak lensing methods, distortions
in the images of faint and distant background galaxies are measured. These distortions are
introduced into the images by the intervening tidal gravitational fields of the clusters along
the line of sight. Comparing the strength of the distortions to theoretical models, mass maps
and density profiles of the lensing clusters are created.
The work includes standard image reduction techniques using the IMCAT software package. Details
about the astrometric calibration, shear measurements, point spread function (PSF) corrections
and the method of mass distribution reconstruction are given, together with a description of
the principles of weak gravitational lensing.
The main results are that both clusters investigated contain a relatively large mass within the
scale of their virial radius. Yet their density profiles are significantly different, in particular
in their central parts. Similar results have been found in the recent years also for different
clusters. The finding of this result was only possible due to the very large field of view
of the CFH12K imager, which allowed to probe the shear field at very different angular scales. | nor |
dc.language.iso | eng | en_US |
dc.subject | galakse-hop gravitasjonslinsing bildereduksjon | en_US |
dc.title | The density profile of clusters of galaxies : Abell 1351 & Abell 1995 | en_US |
dc.type | Master thesis | en_US |
dc.date.updated | 2006-09-01 | en_US |
dc.creator.author | Holhjem, Karianne | en_US |
dc.subject.nsi | VDP::438 | en_US |
dc.identifier.bibliographiccitation | info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft.au=Holhjem, Karianne&rft.title=The density profile of clusters of galaxies&rft.inst=University of Oslo&rft.date=2006&rft.degree=Masteroppgave | en_US |
dc.identifier.urn | URN:NBN:no-12898 | en_US |
dc.type.document | Masteroppgave | en_US |
dc.identifier.duo | 43206 | en_US |
dc.contributor.supervisor | Håkon Dahle, Per B. Lilje | en_US |
dc.identifier.bibsys | 061373788 | en_US |
dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/10932/3/main_smaller.pdf | |