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Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT
To date, our understanding of the formation and evolution of galaxies attributes a very important role to the neutral hydrogen (HI) gas since it constitutes the reservoir of fuel out of which galaxies form stars. In their evolution, galaxies interact with each other and with their environment, and v...
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| Format: | Thesis |
| Language: | English |
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Department of Astronomy
2016
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| _version_ | 1867613232937566208 |
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| access_status_str | Open Access |
| author | Sorgho, Amidou |
| author2 | Carignan, Claude |
| author_browse | Carignan, Claude Sorgho, Amidou |
| author_facet | Carignan, Claude Sorgho, Amidou |
| author_sort | Sorgho, Amidou |
| collection | Thesis |
| description | To date, our understanding of the formation and evolution of galaxies attributes a very important role to the neutral hydrogen (HI) gas since it constitutes the reservoir of fuel out of which galaxies form stars. In their evolution, galaxies interact with each other and with their environment, and very often these interactions leave fingerprints in the HI distribution. The extended HI envelopes of galaxies are sensitive tracers of those tidal interactions. In the present study, we map the HI distribution of galaxies in a ~1.5° X 2.5° region of the Virgo cluster using the Karoo Array Telescope (KAT-7) and the Westerbork Synthesis Radio Telescope (WSRT). With a total observing time of ~78 hours with the KAT-7 and 48 hours with the WSRT, we search for low HI column density features in the region. Despite the different observing time and beam size of the two telescopes, we reach similar column density sensitivities of NHI ~1 X 10¹⁸ atoms cm⁻² over 16.5kms⁻¹. With a new approach, we combine the two observations to map both the large and small scale structures. We detect, out to an unprecedented extent, an HI tail of ~60 kpc being stripped off NGC 4424, a peculiar spiral galaxy. The properties of the galaxy, together with the shape of the tail, suggests that NGC 4424 is a post-merger galaxy undergoing a ram pressure stripping as it falls into the centre of the Virgo Cluster along a filamentary structure. We also give the HI parameters of the galaxies detected. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/16495 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:52.713Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| 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:11427/16495 Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT Sorgho, Amidou Carignan, Claude Van Gorkom, Jacqueline H Hess, Kelley M Astronomy Astrophysics and Space Science To date, our understanding of the formation and evolution of galaxies attributes a very important role to the neutral hydrogen (HI) gas since it constitutes the reservoir of fuel out of which galaxies form stars. In their evolution, galaxies interact with each other and with their environment, and very often these interactions leave fingerprints in the HI distribution. The extended HI envelopes of galaxies are sensitive tracers of those tidal interactions. In the present study, we map the HI distribution of galaxies in a ~1.5° X 2.5° region of the Virgo cluster using the Karoo Array Telescope (KAT-7) and the Westerbork Synthesis Radio Telescope (WSRT). With a total observing time of ~78 hours with the KAT-7 and 48 hours with the WSRT, we search for low HI column density features in the region. Despite the different observing time and beam size of the two telescopes, we reach similar column density sensitivities of NHI ~1 X 10¹⁸ atoms cm⁻² over 16.5kms⁻¹. With a new approach, we combine the two observations to map both the large and small scale structures. We detect, out to an unprecedented extent, an HI tail of ~60 kpc being stripped off NGC 4424, a peculiar spiral galaxy. The properties of the galaxy, together with the shape of the tail, suggests that NGC 4424 is a post-merger galaxy undergoing a ram pressure stripping as it falls into the centre of the Virgo Cluster along a filamentary structure. We also give the HI parameters of the galaxies detected. 2016-01-21T13:01:00Z 2016-01-21T13:01:00Z 2015 Master Thesis Masters MSc http://hdl.handle.net/11427/16495 eng application/pdf Department of Astronomy Faculty of Science University of Cape Town |
| spellingShingle | Astronomy Astrophysics and Space Science Sorgho, Amidou Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| thesis_degree_str | Master's |
| title | Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| title_full | Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| title_fullStr | Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| title_full_unstemmed | Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| title_short | Observing galaxies in the Southern Filament of the Virgo Cluster with KAT-7 and WSRT |
| title_sort | observing galaxies in the southern filament of the virgo cluster with kat 7 and wsrt |
| topic | Astronomy Astrophysics and Space Science |
| url | http://hdl.handle.net/11427/16495 |
| work_keys_str_mv | AT sorghoamidou observinggalaxiesinthesouthernfilamentofthevirgoclusterwithkat7andwsrt |