Research Article
Variation of Total Electron Content over May 10 - 13 2024 Geomagnetic Super Storm in South Africa
Efrem Amanuel Data*
Issue:
Volume 13, Issue 2, June 2025
Pages:
21-35
Received:
4 March 2025
Accepted:
27 March 2025
Published:
11 April 2025
Abstract: This study investigates the variation of Total Electron Content (TEC) over South Africa during the geomagnetic superstorm of May 10 - 13, 2024. This study aims to analyze the variation of TEC over South Africa during the May 10 - 13, 2024, geomagnetic superstorm using data from the IRI-2020 model, GNSS-based TEC measurements, and other geomagnetic parameters. The root mean square error (RMSE) method was applied to quantify the deviations between GPS-derived TEC measurements and the IRI-2020 model during the geomagnetic storm. The results reveal significant TEC fluctuations, with a pronounced increase during the main phase due to prompt penetration electric fields (PPEFs) and storm-induced ionospheric disturbances. This was followed by a sharp TEC depletion in the recovery phase, attributed to thermospheric composition changes, particularly oxygen-to-nitrogen ratio variations. Magnetometer H-component observations further confirm the strong geomagnetic activity associated with the storm, indicating enhanced ionospheric currents and electrodynamic coupling. Latitudinal variations in TEC revealed complex ionospheric dynamics, with more pronounced disturbances at mid-latitudes. The ionospheric irregularities affected GNSS-based positioning, highlighting the impact of geomagnetic storms on navigation systems. These findings provide valuable insights into ionospheric storm effects over South Africa, contributing to improved space weather forecasting, GNSS accuracy, and regional ionospheric modeling.
Abstract: This study investigates the variation of Total Electron Content (TEC) over South Africa during the geomagnetic superstorm of May 10 - 13, 2024. This study aims to analyze the variation of TEC over South Africa during the May 10 - 13, 2024, geomagnetic superstorm using data from the IRI-2020 model, GNSS-based TEC measurements, and other geomagnetic ...
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Research Article
The Interplay Between Supermassive Black Holes and Their Host Galaxies: A Multi-wavelength Approach
Diriba Gonfa Tolasa*
Issue:
Volume 13, Issue 2, June 2025
Pages:
36-48
Received:
12 March 2025
Accepted:
31 March 2025
Published:
22 April 2025
DOI:
10.11648/j.ijass.20251302.12
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Abstract: The interplay between supermassive black holes (SMBHs) and their host galaxies is a critical area of research in extragalactic astronomy, shedding light on the fundamental processes that govern galaxy formation and evolution. This study employs a multi-wavelength approach to investigate the correlation between SMBHs and their host galaxies, utilizing data from radio, optical, infrared, and X-ray observations. Recent advancements in observational technologies have enabled deeper insights into the mechanisms at play in this complex relationship. We begin by examining the fundamental connection between the mass of SMBHs and various properties of their host galaxies, such as stellar mass, bulge structure, and star formation rate. Our analysis reveals a significant correlation between SMBH mass and the central velocity dispersion of stars, consistent with the established M-sigma relation. However, deviations from this correlation suggest the influence of additional factors, such as environmental conditions and galaxy mergers. Furthermore, we explore the feedback mechanisms initiated by SMBHs, particularly through active galactic nuclei (AGN) activity. Multi-wavelength observations allow us to assess the impact of AGN feedback on star formation within host galaxies. We document cases where AGN activity suppresses star formation, resulting in a transition from star-forming to passive galaxies. Conversely, we also identify scenarios where SMBH feedback may trigger star formation, underscoring the dual role of SMBHs in galaxy evolution. In addition to examining individual cases, we utilize large galaxy survey data sets to analyze trends across different galaxy populations. Our findings indicate variations in SMBH-host galaxy relationships based on galaxy morphology and environment, suggesting that the evolution of both components is influenced by cosmic structures. This study highlights the importance of a multi-wavelength approach in understanding the complex dynamics between SMBHs and their host galaxies. By integrating diverse data sources, we provide a comprehensive view of how these colossal entities coexist and interact. Our results contribute to the broader discourse on galaxy formation theories and the role of SMBHs in shaping the universe, paving the way for future investigations that will deepen our understanding of cosmic evolution.
Abstract: The interplay between supermassive black holes (SMBHs) and their host galaxies is a critical area of research in extragalactic astronomy, shedding light on the fundamental processes that govern galaxy formation and evolution. This study employs a multi-wavelength approach to investigate the correlation between SMBHs and their host galaxies, utilizi...
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