| Abstract : | Various solar activities somehow connected to solar differential rotation. Understanding of solar rotation is, therefore, considered as one of the most vital characteristics for solar study. As we know, the rotation of Sun varies not only as a function of altitude but also as function of latitude. Information about the latitudinal differential rotation of the solar atmospheric layers is also required to predict the solar activity and hence space weather. Solar rotation can be estimated either through tracking any tracers on the solar photosphere or chromosphere, or by the spectral analysis of solar limbs, and also through measuring the modulation in the emission of any particular wavelength flux originated from any part of the solar atmosphere. In present study, flux modulation is used which traces the passage of integrated radio feature along the latitude over the solar disc of the Radio-Heliograph at 17 GHz recorded daily at (NoRH), Nobeyama, Japan. Such analysis created a time series of radio data from the radio-heliograph (one image per day) for the period (2010-2019). A total 19 time-series were so obtained from time-series analysis performed at imaginary latitude bins extended from 45º North to 45º South at interval of 5º each. The periodicities present in the time series can be estimated by number of statistical methods such as Autocorrelation, FFT, Wavelet Analysis and/or LSP. In the present work flux modulation method is used to obtain time-series and LSP is used to estimate periodic component present in such time series and hence provides the coronal rotation period as a function of latitude. The results so obtained, for different epoch of study period in solar cycle 24, show rigid rotation as well as differential rotation of solar corona in different epoch. This temporal variation in coronal rotation could be linked to the 11 yrs sunspot cycle. |
