Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The Galaxy Velocity Function from MIGHTEE-HI Early Science Data
The velocity function of MIGHTEE-H I Early Science data is presented. This is the first velocity function that is based on a blind radio interferometric survey. As a precursor, understanding the systematics that affect the Early Science velocity function will optimise the full survey's analysis. PYM...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Astronomy
2022
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613649794760704 |
|---|---|
| access_status_str | Open Access |
| author | Mulaudzi, Wanga |
| author2 | Frank, Bradley |
| author_browse | Frank, Bradley Mulaudzi, Wanga |
| author_facet | Frank, Bradley Mulaudzi, Wanga |
| author_sort | Mulaudzi, Wanga |
| collection | Thesis |
| description | The velocity function of MIGHTEE-H I Early Science data is presented. This is the first velocity function that is based on a blind radio interferometric survey. As a precursor, understanding the systematics that affect the Early Science velocity function will optimise the full survey's analysis. PYMULTINEST and the Busy Function are employed to estimate the linewidths of the low spectral resolution data. The performance of PYMULTINEST in estimating known linewidths of simulated H I profiles with varying spectral resolution is assessed. The simulation study shows that the estimated linewidths of the Early Science data, using this novel method, are robust and are recovered within the uncertainty. The effects of cosmic variance, instrumental linewidth broadening and Doppler linewidth broadening on the velocity function are quantified within the context of the limitations of the Early Science data. The MIGHTEE-H I Early Science velocity function is compared with the velocity functions from previous large-scale H I surveys, namely the Arecibo Legacy Fast ALFA (ALFALFA) survey and the H I Parkes All-Sky Survey (HIPASS). There is general agreement with the ALFALFA and HIPASS results, when taking linewidth broadening into account, given that the MIGHTEE-H I Early Science data is strongly affected by cosmic variance. In particular, cosmic variance introduces an average uncertainty of ∼ 24% in the measured Early Science volume densities. The larger effective area of the full survey will reduce the impact of cosmic variance. The full survey velocity function can be further optimised by estimating the rotational velocities using kinematic modelling, and correcting the measured linewidths for instrumental broadening, Doppler broadening, turbulent motion and inclination effects. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/35959 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:39:30.779Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| 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:11427/35959 The Galaxy Velocity Function from MIGHTEE-HI Early Science Data Mulaudzi, Wanga Frank, Bradley Kraan-Korteweg, Renee Christine Astronomy The velocity function of MIGHTEE-H I Early Science data is presented. This is the first velocity function that is based on a blind radio interferometric survey. As a precursor, understanding the systematics that affect the Early Science velocity function will optimise the full survey's analysis. PYMULTINEST and the Busy Function are employed to estimate the linewidths of the low spectral resolution data. The performance of PYMULTINEST in estimating known linewidths of simulated H I profiles with varying spectral resolution is assessed. The simulation study shows that the estimated linewidths of the Early Science data, using this novel method, are robust and are recovered within the uncertainty. The effects of cosmic variance, instrumental linewidth broadening and Doppler linewidth broadening on the velocity function are quantified within the context of the limitations of the Early Science data. The MIGHTEE-H I Early Science velocity function is compared with the velocity functions from previous large-scale H I surveys, namely the Arecibo Legacy Fast ALFA (ALFALFA) survey and the H I Parkes All-Sky Survey (HIPASS). There is general agreement with the ALFALFA and HIPASS results, when taking linewidth broadening into account, given that the MIGHTEE-H I Early Science data is strongly affected by cosmic variance. In particular, cosmic variance introduces an average uncertainty of ∼ 24% in the measured Early Science volume densities. The larger effective area of the full survey will reduce the impact of cosmic variance. The full survey velocity function can be further optimised by estimating the rotational velocities using kinematic modelling, and correcting the measured linewidths for instrumental broadening, Doppler broadening, turbulent motion and inclination effects. 2022-03-07T12:17:47Z 2022-03-07T12:17:47Z 2021 2022-03-07T11:02:48Z Master Thesis Masters MSc http://hdl.handle.net/11427/35959 eng application/pdf Department of Astronomy Faculty of Science |
| spellingShingle | Astronomy Mulaudzi, Wanga The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| thesis_degree_str | Master's |
| title | The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| title_full | The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| title_fullStr | The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| title_full_unstemmed | The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| title_short | The Galaxy Velocity Function from MIGHTEE-HI Early Science Data |
| title_sort | galaxy velocity function from mightee hi early science data |
| topic | Astronomy |
| url | http://hdl.handle.net/11427/35959 |
| work_keys_str_mv | AT mulaudziwanga thegalaxyvelocityfunctionfrommighteehiearlysciencedata AT mulaudziwanga galaxyvelocityfunctionfrommighteehiearlysciencedata |