Neutron star X-ray binaries with MeerKAT
| dc.contributor.advisor | Monageng, Itumeleng | |
| dc.contributor.advisor | Woudt, Patrick | |
| dc.contributor.author | Gasealahwe, Kelebogile | |
| dc.date.accessioned | 2026-06-18T06:35:18Z | |
| dc.date.available | 2026-06-18T06:35:18Z | |
| dc.date.issued | 2026 | |
| dc.date.updated | 2026-06-18T06:30:57Z | |
| dc.description.abstract | X-ray binaries make up a large fraction of transient systems. These soucres are categorized into black hole and neutron star systems based on the compact object. The dichotomy between neutron star X-ray binaries and black hole X-ray binaries was well established up to the early 2000s. However, the fundamental differences have come into question since the correlation between the radio continuum and X-ray waveband of an increasing amount of neutron stars systems revealed parallel trends to the black hole counterparts. In this study we make use of a sample set of low-mass neutron star X-ray binary systems to investigate the nature of the disc (X ray) and the jet (radio) activity during outburst events. The sample includes SAX J1808.4-3658 an Accreting millisecond pulsar, two transitional Z/Atoll-sources Cir X-1 and XTE J1701-462 and Z-sources Cyg X-2, GX 340+0, GX 17+2, GX 13+1 and GX 349+2. To investigate the disc and jet activity the sources were observed with radio telescopes MeerKAT and AMI and X-ray telescopes Swift-XRT, MAXI and NICER. SAX J1808.4 3658, Cir X-1 and XTE J1701-462 were observed for the full outbursts in 2019, 2021 and 2022/23 respectively. The group of Z-sources only had single observations made in 2021. The outbursts were analysed through radio imaging and examining the lightcurves. Radio flaring events were identified in the lighcurves and the minimum energy of these flares calculated for XTE J1701-462. On the other hand, for Cir X-1, the minimum energy was calculated for the nebula by measuring the size of the structure directly from the radio image. The Cir X-1 image is a deep field L-band radio image, through which we discovered the jets breaking out of the natal supernova remnant in the structure the nebula revealed. By placing the sources on the radio– X-ray our results suggest that some neutron star X-ray binaries follow a similar trend (slope of the plane) as black hole X-ray binaries. Therefore, the physical nature of the compact object may not play a significant role in the relationship of the jet production and the accretion disc of X-ray binaries. | |
| dc.identifier.apacitation | Gasealahwe, K. (2026). <i>Neutron star X-ray binaries with MeerKAT</i>. (). University of Cape Town ,Faculty of Science ,Department of Astronomy. Retrieved from http://hdl.handle.net/11427/43330 | en_ZA |
| dc.identifier.chicagocitation | Gasealahwe, Kelebogile. <i>"Neutron star X-ray binaries with MeerKAT."</i> ., University of Cape Town ,Faculty of Science ,Department of Astronomy, 2026. http://hdl.handle.net/11427/43330 | en_ZA |
| dc.identifier.citation | Gasealahwe, K. 2026. Neutron star X-ray binaries with MeerKAT. . University of Cape Town ,Faculty of Science ,Department of Astronomy. http://hdl.handle.net/11427/43330 | en_ZA |
| dc.identifier.ris | TY - Thesis / Dissertation AU - Gasealahwe, Kelebogile AB - X-ray binaries make up a large fraction of transient systems. These soucres are categorized into black hole and neutron star systems based on the compact object. The dichotomy between neutron star X-ray binaries and black hole X-ray binaries was well established up to the early 2000s. However, the fundamental differences have come into question since the correlation between the radio continuum and X-ray waveband of an increasing amount of neutron stars systems revealed parallel trends to the black hole counterparts. In this study we make use of a sample set of low-mass neutron star X-ray binary systems to investigate the nature of the disc (X ray) and the jet (radio) activity during outburst events. The sample includes SAX J1808.4-3658 an Accreting millisecond pulsar, two transitional Z/Atoll-sources Cir X-1 and XTE J1701-462 and Z-sources Cyg X-2, GX 340+0, GX 17+2, GX 13+1 and GX 349+2. To investigate the disc and jet activity the sources were observed with radio telescopes MeerKAT and AMI and X-ray telescopes Swift-XRT, MAXI and NICER. SAX J1808.4 3658, Cir X-1 and XTE J1701-462 were observed for the full outbursts in 2019, 2021 and 2022/23 respectively. The group of Z-sources only had single observations made in 2021. The outbursts were analysed through radio imaging and examining the lightcurves. Radio flaring events were identified in the lighcurves and the minimum energy of these flares calculated for XTE J1701-462. On the other hand, for Cir X-1, the minimum energy was calculated for the nebula by measuring the size of the structure directly from the radio image. The Cir X-1 image is a deep field L-band radio image, through which we discovered the jets breaking out of the natal supernova remnant in the structure the nebula revealed. By placing the sources on the radio– X-ray our results suggest that some neutron star X-ray binaries follow a similar trend (slope of the plane) as black hole X-ray binaries. Therefore, the physical nature of the compact object may not play a significant role in the relationship of the jet production and the accretion disc of X-ray binaries. DA - 2026 DB - OpenUCT DP - University of Cape Town KW - X-ray binaries LK - https://open.uct.ac.za PB - University of Cape Town PY - 2026 T1 - Neutron star X-ray binaries with MeerKAT TI - Neutron star X-ray binaries with MeerKAT UR - http://hdl.handle.net/11427/43330 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/43330 | |
| dc.identifier.vancouvercitation | Gasealahwe K. Neutron star X-ray binaries with MeerKAT. []. University of Cape Town ,Faculty of Science ,Department of Astronomy, 2026 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/43330 | en_ZA |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Astronomy | |
| dc.publisher.faculty | Faculty of Science | |
| dc.publisher.institution | University of Cape Town | |
| dc.subject | X-ray binaries | |
| dc.title | Neutron star X-ray binaries with MeerKAT | |
| dc.type | Thesis / Dissertation | |
| dc.type.qualificationlevel | Doctoral | |
| dc.type.qualificationlevel | PhD |