[1] The International Reference Ionosphere (IRI) model has been widely adopted as the international standard for specifying ionospheric parameters. An evaluation on the performance of the IRI model (version 2007) over Nsukka, Nigeria (Geographic: 6.87 N, 7.38 E; Geomagnetic: 8.47 N, 81.07 E) is presented in this work. We compare Total Electron Content (TEC) values for year 2010 from the IRI model with corresponding TEC data from the SCINDA (Scintillation Network Decision Aid) GPS receiver installed at Nsukka so as to evaluate the performance of the model over the Nsukka region. Given the proliferation of dual-frequency GPS receivers over the African continent, data from these equipment is proposed for use in TEC modeling over the continent together with the IRI model. Knowledge on the performance of the IRI over various regions of the continent will inform the extent to which the model will be used. The development of more accurate TEC maps find useful applications in enhancing the extent to which ionospheric influences on radio signals (as in single frequency GPS receivers) are corrected. Our results show very good diurnal correlations (above 0.88) between the IRI-TEC predictions and the GPS-TEC measurements for the days examined, and so reveal the potential of the IRI model as a good candidate for an enhanced TEC modeling over the African region.

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We carried out spectroscopic analysis of the extracted stellar flare of the Algol binary system observed using the Suzaku satellite (OBSID: 401093010), and resolved a strong 6.7 keV line emission. The 6.7 keV line emission of the Algol binary system is similar to the 6.7 keV line of the galactic ridge X-ray emission (GRXE). The equivalent width (EW) compared favorably with the EW of the 6.7 keV emission line obtained from different galactic ridge regions. In the galaxy, we have a reasonable number of Algol binary systems and many other stars as strong coronal X-ray emitters characterized by frequent quiescent and super flaring phases as observed by Suzaku, and these systems could contribute to the 6.7 keV emission line from the galactic ridge.

We present spectral analysis of Algol stellar flare data. The 2-day observation of Algol in our Galaxy was done by Suzaku Satellite. Algol binary system consists of two component stars that eclipse one another periodically. The stellar magnetic field activities and Roche Lobe overflow/mass transfer mechanisms during rapid rotation of the component stars generate an X-ray emission. The variation in brightness of the stellar flare from epoch to epoch provides useful information of stellar properties of the component stars. The atomic physics of the Kα line emission process in the vicinities of chromospherically active and X-ray flare stars, and binaries is well understood. The photo ionization/collisional excitation in the Algol's corona produces 6.7 keV line emission. The accumulated spectra in X-ray Imaging Spectrometer (XIS) sensors fitted combined with bremsstrahlung model and Gaussian line show a strong fixed X-ray energy of 6.7 keV.

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