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Measurements of the scatter pulse broadening of pulsar radio emission

Measurements of the scatter pulse broadening of pulsar radio emission and a homogeneity of the turbulent plasma in the near Galaxy A.D. Kuzmin & B.Ya. Losovsky Pushchino Radio Astronomy Observatory, Lebedev Physical Institute, Russia.

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Measurements of the scatter pulse broadening of pulsar radio emission

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  1. Measurements of the scatter pulse broadening of pulsar radio emission and a homogeneity of the turbulent plasma in the near GalaxyA.D. Kuzmin & B.Ya. Losovsky Pushchino Radio Astronomy Observatory, Lebedev Physical Institute, Russia

  2. We report the low-frequency measurements of a scatter broadening of the most complete uniform set of 100 pulsars, in the vast Galaxy region of Galactic longitude from 6оto 252о and distances up to 3 kpc Low frequency expands a frequency interval of sc data and provide more precise determination of the frequency dependence sc(ν) ν- Large sample of 100 pulsars and uniform measurements and reduction processes provide more precise determination of a dispersion measure dependencesc(DM) DM The vast scope of the Galaxy provide a study of distribution of Galactic scattering material Our Low-frequency study is bounded by dispersion measure of about 100 cm-3 pc, therefore our scope related to the near Galaxy ( d  3 kpc).

  3. Measurements are performed in 2004 and 2005The major part of observations were carried out at 111 MHz used the Large Phased Array (BSA) Radio Telescope at Pushchino Radio Astronomy Observatory

  4. An example of th observed scattered Giant pulses of Crab pulsar at 111 MHz

  5. An additional observations were performed at 40 an 60 MHz with the DKR Radio Telescope

  6. Giant pulse of Crab pulsar as observed at 43 MHz

  7. The scatter broadening magnitude was determined by matching the observed pulse with the convolution of the Gaussian template with thin screen scattering function G(t)=exp(-t/sc ) An example of the scatter pulse broadening determination for the Crab pulsar

  8. Large sample of 100 pulsars and uniform measurements and reduction processes provide a more precise determination of a dispersion measure dependence sc (DM)  DM Dispersion measure dependence index is obtained as  = 2.20,1, that corresponds to the uniform Kolmogorov spectrum of turbulence

  9. Low frequency measurements (110, 60 and 40 MHz) and other data form literature expand several times the frequency interval of sc data and provide the more precise determination of the frequency dependence Frequency interval max /min=55 (402228 МГц) -

  10. For precise determination of the frequency dependence sc (ν) νwe used 18 pulsars, for which our and reference data span a frequency interval of max /min 10

  11. Table 2. Frequency dependence of the scatter broadening Mean index of frequency dependence  = 4.1  0.3 fit to the normal distribution of irregularities scale

  12. The vast scope of the Galaxy allows to analyze the distribution of the Galactic scattering material in 100 lines of sight and distancesup to 3 kpc.

  13. The measurements of sc was used to estimate the average scattering parameter Cn2

  14. Level of turbulence Cn2 via Galactic longitude In the range of d  3 kpc one doesn't note a noticible change of Cn2 with the Galaxy longitude

  15. Level of turbulence Cn2vs. distance from the Earth In the range of d  3 kpc one don't note a noticible dependence of Cn2 on the distance from the Earth both to the Galaxy center and anticenter.

  16. In a near Galaxy region up to the distance d  3 kpc the electron density large scale turbulence is uniformly distributed.

  17. The work under progress We realized a new way of a remote sensing of the solar corona by measurements of the pulse scatter broadening in occultation state.

  18. Conclusions 1. One performs the uniform low-frequency measurements of scatter broadening of the most complete set of 100 pulsars in the vast Galaxy region of Galactic longitude 6о- 252о and distances up to 3 kpc. 2. Dispersion measure dependence index was determined as  = 2.20,1 that corresponds to uniform Kolmogorov spectrum of turbulence 3. Mean index of frequency dependence was determined as  = 4.1  0.3 that fit to normal distribution of irregularities scale 4. In the near Galaxy region up to the distance d  3 kpc the large scale electron density turbulenceis uniformly distributed. 5. The new ways for a probing solar corona by a pulsar temporal scatter broadening was proposed and realized.

  19. Thank you !

  20. A wide scatter of measured values of  index may be arise from a narrow frequency interval 1 / 2 of this measurements. For instance, Bhat et al. (2005) determinated the  index in 1 / 2 = 1.25 ! For 15% sc measurements error In the frequency interval of 1 / 2 = 1.25 -value scatter from 2.7 to 5.3 In the frequency interval of 1 / 2 = 15 -value scatter from 3.9 to 4.1 One need low- frequency observations.

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