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Fourier Transforms on Simulated Pulsar Data Gamma-ray Large Area Space Telescope.

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Presentation on theme: "Fourier Transforms on Simulated Pulsar Data Gamma-ray Large Area Space Telescope."— Presentation transcript:

1 Fourier Transforms on Simulated Pulsar Data Gamma-ray Large Area Space Telescope

2 Basic Pulsar Create series of evens distributed over 500 000s (5.7 days) Period of pulsar P 0 = 0.1 s Number of events ~ 500 (= bright Geminga like pulsar) Calculate the number of turns from the pulsar for the photon n turns n = F 0 * t n phase n = turns n – int (turns n )

3 Fourier Transform Calculate the Fourier Transform power = sqrt ((  sin (2  phase n )) 2 + (  cos (2  phase n )) 2 ) /n

4 Fourier Transform on Differences Calculate the number between two photons (i,j, i<j ) turns n = F 0 * (t j – t i ) where (t j – t i ) < max_diff phase n = turns n – int (turns n ) power = sqrt ((  sin (2  phase n )) 2 + (  cos (2  phase n )) 2 ) /n max_diff = 5000s

5 Re and Im part of the FT Power Re Im Phase offset 0 * 2 

6 Re and Im part of the FT Power Re Im Phase offset 0.3 * 2 

7 Re and Im part of the FT Power Re Im Phase offset 0 * 2 

8 Dependence on max_diff The influence of max_diff on the Signal to noise ratio

9 Dependence on max_diff The dependance of the signal with in the power spectrum on max_diff Pulse width ~ 1/max_diff

10 Adding a Gaussian distribution Phase diagram Normal FT FT on differences Sigma = P/5 Sigma = P/20Sigma = P/100

11 Adding a pulse

12 Adding a period derivative max_diff = 100 000 s

13 Adding a period derivative The dependence of the signal with in the power spectrum on max_diff

14 Adding a period derivative


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