Interstellar scattering of pulsar pulses at low frequencies

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Session 78 -- Pulsars and Neutron Stars
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

[78.10] Interstellar scattering of pulsar pulses at low frequencies

Yu.P.Shitov (P.N.Lebedev Physical Institute, Russia)

The measurements of the pulse broadening $T_{\rm sc}$ due to interstellar scattering on 23 pulsars at 30, 40, 60 and 103 MHz by using radiotelescopes in Pushchino (Russia) are presented. For a number of available pulsars the frequency dependence $T_{\rm sc}(f) = kf^\alpha$, where power $\alpha=4.3 - 4.8$ for different sources, was obtained. Dispersion measure (DM) dependence of scattering is steeper significantly, than the expected slope for simple models of medium. For all observed pulsars in DM interval 20 - 250 pc cm$^{-3}$ averaged value $T_{\rm sc}(DM) = 0.06 DM^{3.0 \pm 0.2} (\mu s)$, evaluated to 103 MHz. For not very distant pulsars with DM $\la$ 100 (16 pulsars) DM dependence even more steeper: $T_{\rm sc}(DM) = 0.002 DM^{3.8 \pm 0.3} (\mu s)$. These results are consistent with the relations, obtained by Cordes et al. (ApJ.,1985,v288,221) and Alurkar et al. (Aust.J.Phys.,1986,v39,433) at more higher frequencies and show also that spectrum of interstellar plasma turbulence cannot be represented by a simple power law.

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