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Diffraction scintillation at 1.4 and 4.85GHz V.M.Malofeev, O.I.Malov, S.A.Tyul’bashev PRAO, Russia W.Sieber Hochschule Nederrhein, Germany A.Jessner, R.Wielebinski MPIfR, Germany
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Introduction Most important characteristic of the turbulent interstellar medium is the three-dimensional spatial spectrum of the electron density fluctuations: a Gaussian or power law. The aim of our project was to obtain the form of turbulence spectrum for different regions of the sky and for pulsars which are at different distances.
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Observations 100m RT in Effelsberg during 2-12th Sept. 2003 15 pulsars at 1.4GHz and 6 at 4.85GHz Criteria: strong objects with good SNR, pulsars should clearly show scintillation to obtain dynamic spectra the total receiver bandwidht must be much broader then the decorrelation bandwidth of pulsars 1.4GHz: 30chan x 1.33MHz= 40MHz 4.85GHz: 8chan x 60MHz=480MHz two polarization; flux measurements every 30sec; duration of observations 1-10hours
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PSR 0329+54 (1.41GHz) Example of dynamic spectra in the strong scintillation regime
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PSR 1929+10 (1.4GHz; 7 Sept.) Example of dynamic spectra in the weak(?) scin.regime
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PSR 1929+10 (1.4GHz) Scin. data; ACF time function; CCF frequency function; power spectrum; structure function
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PSR 2020+28 (1.4GHz) 03 Sept. - strong scint; 10 Sept. - lensing effect
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PSR 2020+28 (1.4GHz) Scint. data; ACF time function; CCF frequency function; power spectrum structure function
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PSR 1642-03 (4.85GHz) Dynamic spectra in the weak scin. regime
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PSR 0355+54 (4.85GHz) Dynamic spectra in the strong(?) scin.regime
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PSR 0355+54 Scint. data; ACF time function CCF frequency function Power spectrum Structure function
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Number of pulsars
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Conclusion We have obtained scintillation data for 11 PSR at 1.4GHz and 5 PSR at 4.85GHz: the decorrelation time and bandwidth, power low index for spectra and structure function Possible lensing effect (focal spot effect) have been detected for a few pulsars near the critical frequency
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