On the structure of quasi-Keplerian accretion discs surrounding millisecond X-ray pulsars
| dc.contributor.author | Habumugisha, Isaac | |
| dc.contributor.author | Tessema, Solomon B. | |
| dc.contributor.author | Jurua, Edward | |
| dc.contributor.author | Anguma, Simon Katrini | |
| dc.date.accessioned | 2020-10-13T09:48:07Z | |
| dc.date.available | 2020-10-13T09:48:07Z | |
| dc.date.issued | 2020-10-12 | |
| dc.description.abstract | In this study, we investigated the time-independent dynamics (disc structure, forces and torques) of a quasi-Keplerian disc around a millisecond pulsar (MSP) with an internal dynamo. We considered the disc around a MSP to be divided into the inner, middle and outer regions. By assuming that the disc matter flows in a quasi-Keplerian motion, we derived analytical equations for a complete structure (temperature, pressure, surface density, optical depth and magnetic field) of a quasi-Keplerian thin accretion disc, and the pressure gradient force (PGF). In our model, the MSP-disc interaction results into magnetic and material torques, such that for a given dynamo (ϵ) and quasi-Keplerian (ξ) parameter, we obtained enhanced spin-up and spin-down torques for a chosen star spin period. Results obtained reveal that PGF results into episodic torque reversals that contribute to spinning-up or spinning-down of a neutron star, mainly from the inner region. The possibility of a quasi-Keplerian disc is seen and these results can explain the observed spin variations in MSPs like SAX J1808.4-3658 and XTE J1814-338. | en_US |
| dc.description.sponsorship | International Science Programme (ISP) | en_US |
| dc.identifier.citation | Habumugisha, I., Tessema, S.B., Jurua, E. et al. On the structure of quasi-Keplerian accretion discs surrounding millisecond X-ray pulsars. J Astrophys Astron 41, 24 (2020). https://doi.org/10.1007/s12036-020-09643-w | en_US |
| dc.identifier.uri | https://dir.muni.ac.ug/handle/20.500.12260/362 | |
| dc.publisher | Springer | en_US |
| dc.relation.ispartofseries | ;41 | |
| dc.subject | 97.80.Jp X-ray binaries | en_US |
| dc.subject | 97.60.Gb pulsars | en_US |
| dc.subject | 97.10.Gz accretion and accretion discs | en_US |
| dc.title | On the structure of quasi-Keplerian accretion discs surrounding millisecond X-ray pulsars | en_US |
| dc.type | Article | en_US |