The Vela Supercluster - does it provide the missing link to explain the local flow fields?

Simple item page
dc.contributor.advisorKraan-Korteweg, Renée Cen_ZA
dc.contributor.advisorCluver, Michelle Een_ZA
dc.contributor.authorElagali, Ahmeden_ZA
dc.date.accessioned2016-01-25T11:54:23Z
dc.date.available2016-01-25T11:54:23Z
dc.date.issued2015en_ZA
dc.descriptionIncludes bibliographical referencesen_ZA
dc.description.abstractAs part of a larger effort to uncover the structures hidden behind the Milky Way, we analyse 5,190 spectroscopic redshifts for galaxies in the Hydra/Antlia and Vela regions (245°≤ l ≤ 295°, /b/ ≤ 10°). These galaxies are based on deep optical galaxy source catalogues in the Zone of Avoidance in the Hydra/Antlia region (Kraan-Korteweg 2000a), the Vela region (von Maltitz 2012), and the near infrared 2MASS Extended Source Catalogue(XSC) (Jarrett et al. 2000a, Skrutskie et al. 2006). The observed redshifts were mainly obtained from the 2dF+ AAOmega spectrograph at the Anglo-Australian Telescope (80% of the redshifts); the remaining data are from other telescopes as well as from the literature. This analysis is suggestive of the existence of a massive supercluster in this region, hereafter called the Vela Supercluster (VSC). The prospective VSC is at a mean redshift of cz ~18, 000km s⁻¹, and extends approximately about 87 x 87Mpc on-sky. We use a nearest neighbour algorithm to identify the galaxy clusters and groups within the potential VSC, determine their velocity dispersions and the corresponding virial masses. Although the VSC is sparsely sampled, we find 13 galaxy clusters and 22 galaxy groups contained within it. The richness and the masses of these galaxy clusters/groups are comparable with the galaxy clusters/groups found within the Shapley Supercluster by Proust et al. (2006). Taking account of the sparse sampling, the VSC seems comparable to the Shapley Supercluster (SSC). Given the fact that the SSC contributes about 9% of the Local Group motion (Muñoz & Loeb 2008), if not more (see Kocevski & Ebeling 2006). The proximity of a further supercluster (VSC) in its vicinity, might have serious implications on the bulk flows studies. Consequently, the existence of this supercluster is likely key in resolving the long-enduring bulk flow controversies and the misalignment of flows with the dipole determined via the Cosmic Microwave Background (CMB) observations.en_ZA
dc.identifier.apacitationElagali, A. (2015). <i>The Vela Supercluster - does it provide the missing link to explain the local flow fields?</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Astronomy. Retrieved from http://hdl.handle.net/11427/16540en_ZA
dc.identifier.chicagocitationElagali, Ahmed. <i>"The Vela Supercluster - does it provide the missing link to explain the local flow fields?."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Astronomy, 2015. http://hdl.handle.net/11427/16540en_ZA
dc.identifier.citationElagali, A. 2015. The Vela Supercluster - does it provide the missing link to explain the local flow fields?. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Elagali, Ahmed AB - As part of a larger effort to uncover the structures hidden behind the Milky Way, we analyse 5,190 spectroscopic redshifts for galaxies in the Hydra/Antlia and Vela regions (245°≤ l ≤ 295°, /b/ ≤ 10°). These galaxies are based on deep optical galaxy source catalogues in the Zone of Avoidance in the Hydra/Antlia region (Kraan-Korteweg 2000a), the Vela region (von Maltitz 2012), and the near infrared 2MASS Extended Source Catalogue(XSC) (Jarrett et al. 2000a, Skrutskie et al. 2006). The observed redshifts were mainly obtained from the 2dF+ AAOmega spectrograph at the Anglo-Australian Telescope (80% of the redshifts); the remaining data are from other telescopes as well as from the literature. This analysis is suggestive of the existence of a massive supercluster in this region, hereafter called the Vela Supercluster (VSC). The prospective VSC is at a mean redshift of cz ~18, 000km s⁻¹, and extends approximately about 87 x 87Mpc on-sky. We use a nearest neighbour algorithm to identify the galaxy clusters and groups within the potential VSC, determine their velocity dispersions and the corresponding virial masses. Although the VSC is sparsely sampled, we find 13 galaxy clusters and 22 galaxy groups contained within it. The richness and the masses of these galaxy clusters/groups are comparable with the galaxy clusters/groups found within the Shapley Supercluster by Proust et al. (2006). Taking account of the sparse sampling, the VSC seems comparable to the Shapley Supercluster (SSC). Given the fact that the SSC contributes about 9% of the Local Group motion (Muñoz & Loeb 2008), if not more (see Kocevski & Ebeling 2006). The proximity of a further supercluster (VSC) in its vicinity, might have serious implications on the bulk flows studies. Consequently, the existence of this supercluster is likely key in resolving the long-enduring bulk flow controversies and the misalignment of flows with the dipole determined via the Cosmic Microwave Background (CMB) observations. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - The Vela Supercluster - does it provide the missing link to explain the local flow fields? TI - The Vela Supercluster - does it provide the missing link to explain the local flow fields? UR - http://hdl.handle.net/11427/16540 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/16540
dc.identifier.vancouvercitationElagali A. The Vela Supercluster - does it provide the missing link to explain the local flow fields?. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Astronomy, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/16540en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Astronomyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherAstronomyen_ZA
dc.titleThe Vela Supercluster - does it provide the missing link to explain the local flow fields?en_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_2015_elagali_ahmed.pdf
Size:
5.35 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters