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Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm

A galaxy group catalogue for the recently-completed 2MASS Redshift Survey (2MRS, Macri et al., 2019) is presented which consists of 44572 redshifts, including 1041 new measurements for galaxies mostly located within the Zone of Avoidance. The galaxy group catalogue is generated using a novel, graph-...

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Main Author: Lambert, Trystan
Other Authors: Kraan-Korteweg, Renee Christine
Format: Thesis
Language:English
Published: Department of Astronomy 2021
Subjects:
Astrophysics
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access_status_str Open Access
author Lambert, Trystan
author2 Kraan-Korteweg, Renee Christine
author_browse Kraan-Korteweg, Renee Christine
Lambert, Trystan
author_facet Kraan-Korteweg, Renee Christine
Lambert, Trystan
author_sort Lambert, Trystan
collection Thesis
description A galaxy group catalogue for the recently-completed 2MASS Redshift Survey (2MRS, Macri et al., 2019) is presented which consists of 44572 redshifts, including 1041 new measurements for galaxies mostly located within the Zone of Avoidance. The galaxy group catalogue is generated using a novel, graph-theory based, modified version of the Friends-of-Friends algorithm. Several graph-theory examples are presented throughout this paper, and include a new method to identify substructures within groups. The results and graph-theory methods have been thoroughly interrogated against previous 2MRS group catalogues and a Theoretical Astrophysical Observatory (TAO) mock by making use of cutting-edge visualization techniques including immersive facilities, a digital planetarium, and virtual reality. This has resulted in a stable and robust catalogue with on-sky positions and line-of-sight distances within 0.5 Mpc and 2 Mpc of the group respectively. It has recovered all major groups and clusters. The final catalogue consists of 3022 groups, resulting in the most complete “whole-sky” galaxy group catalogue to date. The 3D-positions of the groups are presented, as well as their luminosity and comoving distances, observed and corrected number of members, richness metric, velocity dispersion, and estimates of R200 and M200. Three additional catalogues are provided: 2MRS galaxies found in groups, a catalogue of subgroups, and the catalogue of 687 new group candidates which had no counterparts in previous 2MRS-based analyses.
format Thesis
id oai:open.uct.ac.za:11427/32785
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:32:13.078Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2021
publishDateRange 2021
publishDateSort 2021
publisher Department of Astronomy
publisherStr Department of Astronomy
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/32785 Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm Lambert, Trystan Kraan-Korteweg, Renee Christine Jarrett, Thomas H. Astrophysics A galaxy group catalogue for the recently-completed 2MASS Redshift Survey (2MRS, Macri et al., 2019) is presented which consists of 44572 redshifts, including 1041 new measurements for galaxies mostly located within the Zone of Avoidance. The galaxy group catalogue is generated using a novel, graph-theory based, modified version of the Friends-of-Friends algorithm. Several graph-theory examples are presented throughout this paper, and include a new method to identify substructures within groups. The results and graph-theory methods have been thoroughly interrogated against previous 2MRS group catalogues and a Theoretical Astrophysical Observatory (TAO) mock by making use of cutting-edge visualization techniques including immersive facilities, a digital planetarium, and virtual reality. This has resulted in a stable and robust catalogue with on-sky positions and line-of-sight distances within 0.5 Mpc and 2 Mpc of the group respectively. It has recovered all major groups and clusters. The final catalogue consists of 3022 groups, resulting in the most complete “whole-sky” galaxy group catalogue to date. The 3D-positions of the groups are presented, as well as their luminosity and comoving distances, observed and corrected number of members, richness metric, velocity dispersion, and estimates of R200 and M200. Three additional catalogues are provided: 2MRS galaxies found in groups, a catalogue of subgroups, and the catalogue of 687 new group candidates which had no counterparts in previous 2MRS-based analyses. 2021-02-04T14:02:03Z 2021-02-04T14:02:03Z 2020 2021-02-03T15:14:56Z Master Thesis Masters MSc http://hdl.handle.net/11427/32785 eng application/pdf Department of Astronomy Faculty of Science
spellingShingle Astrophysics
Lambert, Trystan
Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
thesis_degree_str Master's
title Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
title_full Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
title_fullStr Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
title_full_unstemmed Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
title_short Galaxy groups in the updated 2MRS using a graph-theory based friends-of-friends algorithm
title_sort galaxy groups in the updated 2mrs using a graph theory based friends of friends algorithm
topic Astrophysics
url http://hdl.handle.net/11427/32785
work_keys_str_mv AT lamberttrystan galaxygroupsintheupdated2mrsusingagraphtheorybasedfriendsoffriendsalgorithm

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