Physics: Recent submissions

Now showing items 21-40 of 95

    • The spectacular cluster chain Abell 781 as observed with LOFAR, GMRT, and XMM-Newton 

      Botteon, A; Shimwell, T. W; Bonafede, A; Dallacasa, D; Gastaldello, F; Eckert, D; Brunetti, G; Venturi, T; van Weeren, R. J; Mandal, S; Brüggen, M; Cassano, R; de Gasperin, F; Drabent, A; Dumba, C; Intema, H. T; Hoang, D. N; Ra erty, D; Röttgering, H. J. A; Savini, F; Shulevski, A; Stroe, A; Wilber, A (Astronomy & Astrophysics, 2019)
      Context. A number of merging galaxy clusters show the presence of large-scale radio emission associated with the intra-cluster medium (ICM). These synchrotron sources are generally classified as radio haloes and radio ...

    • The LOFAR Two-metre Sky Survey 

      Shimwell, T. W; Tasse, C.; Hardcastle, M. J; Mechev, A. P; Williams, W. L; Best, P. N; Röttgering, H. J. A; Callingham, J. R; Dijkema, T. J; de Gasperin, F; Hoang, D. N; Hugo, B; Mirmont, M; Oonk, J. B. R; Prandoni, I; Ra erty, D; Sabater, J; Smirnov, O; van Weeren, R. J; White, G. J; Atemkeng, M; Bester, L; Bonnassieux, E; Brüggen, M; Brunetti, G; Chy˙zy, K. T; Cochrane, R; Conway, J. E; Croston, J. H (Astronomy & Astrophysics, 2019)
      The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120–168MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. ...

    • Study of Chemically Peculiar Stars-III: High-resolution Spectroscopy and K2 Photometry of New Variables in the Region of M44 

      Joshi, Santosh; Trust, Otto; Williams, P. E.; Semenko, E.; Cat, P. De; Jurua, E.; Holdsworth, D. L.; Garcıa, R. A.; Abedigamba, O. P. (Sub-Saharan Africa Astronomy Summer School, 2022)
      We aim to carry out a study on the photometric and spectroscopic variabilities of four stars monitored in the Nainital- Cape survey. We analysed the photometric variability of the target stars, HD73135,BD+19° 2045, BD+19° ...

    • Starspots and Rotation Velocities of Normal A- And Am- Stars 

      Trust, O; Jurua, E; Cat, P. De; Joshi, S (Stars and their Variability Observed from Space, 2020)
      Using the \hump and spike" features, we computed the rotation frequencies and amplitudes. The corresponding equatorial rotational velocity (Vrot) and spot size were estimated. On _tting the auto-correlation functions of ...

    • Probing Accretion Disk Winds in AGN 

      Dumba, Cosmos (arXiv preprint arXiv, 2014)
      The Broad Line Region of Active Galactic Nuclei is characterized by broad Balmer emission lines in their optical spectra. The broad Balmer emission lines are found to be asymmetric, some blue sided and others red sided in ...

    • New mysteries and challenges from the Toothbrush relic: wideband observations from 550MHz to 8GHz 

      Rajpurohit, K.; Hoeft, M.; Vazza, F.; Rudnick, L.; Weeren, R. J. van; Wittor, D.; Drabent, A.; Brienza, M.; Bonnassieux, E.; Locatelli, N.; Kale, R.; Dumba, C. (Astronomy & Astrophysics, 2020)
      Context. Radio relics are di_use extended synchrotron sources that originate from shock fronts induced by galaxy cluster mergers. The particle acceleration mechanism at the shock fronts is still under debate. The galaxy ...

    • Effects of space weather on the ionosphere: A case study of geomagnetic storms during 17-28 February 2014 

      Aol, Sharon; Mungufeni, Patrick; Jurua, Edward (Indian Journal of Radio & Space Physics, 2020)
      This study focused on the effects of space weather on the ionosphere during geomagnetic storms for the period 17-28 February 2014 over the African low, latitude region. The Global Positioning System (GPS) data, derived ...

    • Abell 1430: A merging cluster with exceptional diffuse radio emission 

      Hoeft, M; Dumba, C; Drabent, A.; Rajpurohit, K.; Rossetti, M.; Nuza, S. E.; Weeren, R. J. van; Meusinger, H.; Botteon, A.; Brunetti, G.; Shimwell, T. W.; Cassano, R.; Brüggen, M.; Röttgering, H. J. A.; Gastaldello, F.; Lovisari, L.; Yepes, G.; Andrade-Santos, F.; Eckert, D. (Astronomy and Astrophysics, 2021)
      Context. Di_use radio emission has been found in many galaxy clusters, predominantly in massive systems which are in the state of merging. The radio emission can usually be classified as relic or halo emission, which are ...

    • Spatio-Temporal Variation in the Concentration of Inhalable Particulate Matter (PM10) in Uganda 

      Onyango, Silver; Parks, Beth; Anguma, Simon; Meng, Qingyu (International journal of environmental research and public health, 2019)
      Long-term particulate matter (PM10) measurements were conducted during the period January 2016 to September 2017 at three sites in Uganda (Mbarara, Kyebando, and Rubindi) representing a wide range of urbanization. Spatial, ...

    • The Study of Variability of 8 Blazar Candidates Among the Fermi-LAT Unidentified Gamma-Ray Sources 

      P, Nkundabakura; D’amour, Kamanzi J; D, Mbarubucyeye J; T, Mutabazi (Proceedings of the International Astronomical Union, 2019)
      We discuss the time-series behavior of 8 extragalactic 3FGL sources away from the Galactic plane (i.e., | b |> 10◦ ) whose uncertainty ellipse contains a single X-ray and one radio source. The analysis was done using the ...

    • The flare-activity of 2MASS J16111534–1757214 in the upper Scorpius association 

      Guenther, E. W; Wockel, D; Chaturvedi, P; Kumar, V; Srivastava, M. K; Muheki, P (Monthly Notices of the Royal Astronomical Society, 2021)
      Flares are known to play an important role for the evolution of the atmospheres of young planets. In order to understand the evolution of planets, it is thus important to study the flare-activity of young stars. This is ...

    • The Norma cluster (ACO 3627) – III. The Distance and Peculiar Velocity via the Near-Infrared Ks-band Fundamental Plane. 

      Mutabazi, T; Blyth, S. L; Woudt, P. A; Lucey, J. R; Jarrett, T. H; Bilicki, M; Schroder, A. C; Moore, S. A. W (Monthly Notices of the Royal Astronomical Society, 2014)
      While Norma (ACO 3627) is the richest cluster in the Great Attractor (GA) region, its role in the local dynamics is poorly understood. The Norma cluster has a mean redshift (zCMB) of 0.0165 and has been proposed as the ...

    • Validation of the Atmospheric Boundary Layer Height Estimated from the MODIS Atmospheric Profile Data at an Equatorial Site 

      Onyango, Silver; Anguma, Simon K; Andima, Geoffrey; Parks, Beth (Atmosphere, 2020)
      The atmospheric boundary layer height is important for constraining air pollution and meteorological models. This study attempted to validate the MODIS-estimated atmospheric boundary layer height (ABLH), and variation in ...

    • Performance Of A Conventional Solar Dryer Under Local Climatic Conditions Of Mbarara In Uganda 

      Trust, Otto; Okot, David Kilama (Journal of Agriculture, 2018)
      Open-air sun drying of agricultural products is still practiced largely in ways unchanged from ancient times after harvest. There is always contamination, theft or damage by birds, rats or insects; slow or intermittent ...

    • Classification of Fuzzy Logic Linguistic Terms for Accurate Load Balancing in Electric Power Distribution System. 

      Atim, Michael Robson; Anguma, Simon Katrini; Nabende, Jimmy Wanzala (International Conference on Electrical, Computer and Energy Technologies (ICECET), 2021)
      Intelligent controls in electric power distribution system can be used to improve electric power distribution by balancing loads in a three-phase system at any time. One of such intelligent controls is fuzzy logic. In this ...

    • AI Based Wireless Traffic Light Detector using Image Classification in Machine Learning to Reduce Road Traffic Accidents: A Case Study of Uganda’s Road Traffic 

      Wanzala, J.N; Atim, M.R (International Journal of Electronics Communication and Computer Engineering, 2021)
      Road traffic accidents in Uganda have led to many deaths. This unfortunately occurs to pedestrians, users of private and public means of transportations. Many solutions have however focused on for example: sensitization, ...

    • Cosmological perturbations in f(G) gravity 

      Munyeshyaka, Albert; Ntahompagaze, Joseph; Mutabazi, Tom (International Journal of Modern Physics D, 2021)
      We explore cosmological perturbations in a modified Gauss-Bonnet f(G) gravity, using a 1+3 covariant formalism. In such a formalism, we define gradient variables to get perturbed linear evolution equations. We transform ...

    • Rotation and spots in normal A and Am/Fm stars 

      Trust, Otto; Jurua, Edward; Cat, Peter De; Joshi, Santosh (Monthly Notices of the Royal Astronomical Society, 2020)
      Frequency analysis of long-term ultraprecise photometry can lead to precise values of rotation frequencies of rotating stars with ‘hump and spike’ features in their periodograms. Using these features, we computed the ...

    • Are the observed gaps in protoplanetary discs caused by growing planets? 

      Ndugu, N; Bitsch, B; Jurua, E (Monthly Notices of the Royal Astronomical Society, 2019)
      Recent detailed observations of protoplanetary discs revealed a lot of substructures that are mostly ring like. One interpretation is that these rings are caused by growing planets. These potential planets are not yet ...

    • Tracking the Ionospheric Response to the Solar Eclipse of November 03, 2013 

      Amabayo, Emirant Bertillas; Anguma, Simon Katrini; Jurua, Edward (International Journal of Atmospheric Sciences, 2014)
      The ionospheric dynamics is highly influenced by the solar radiation. During a solar eclipse, the moon occults the solar radiation from reaching the ionosphere, which may drastically affect the variability of the ionosphere. ...