The Thousand-Pulsar-Array programme on MeerKAT -- V. Scattering analysis of single-component pulsars

TL;DR

This study measures scattering timescales and spectral indices for 84 pulsars using MeerKAT, revealing a mean spectral index of 4.0 and supporting an isotropic scattering model, aiding future scattering research.

Contribution

First comprehensive scattering analysis of single-component pulsars with MeerKAT, providing valuable data for understanding interstellar scattering effects.

Findings

Mean spectral index α = 4.0 ± 0.6

Isotropic scatter broadening model fits data well

Sample includes distant, high dispersion measure pulsars

Abstract

We have measured the scattering timescale, $\tau$, and the scattering spectral index, $\alpha$, for 84 single-component pulsars. Observations were carried out with the MeerKAT telescope as part of the Thousand-Pulsar-Array programme in the MeerTime project at frequencies between 0.895 and 1.670 GHz. Our results give a distribution of values for $\alpha$ (defined in terms of $\tau$ and frequency $\nu$ as $\tau\propto\nu^{-\alpha}$) for which, upon fitting a Gaussian, we obtain a mean and standard deviation of $\langle\alpha\rangle = 4.0 \pm 0.6$. This is due to our identification of possible causes of inaccurate measurement of $\tau$, which, if not filtered out of modelling results, tend to lead to underestimation of $\alpha$. The pulsars in our sample have large dispersion measures and are therefore likely to be distant. We find that a model using an isotropic scatter broadening function is consistent with the data, likely due to the averaging effect of multiple scattering screens along the line of sight. Our sample of scattering parameters provides a strong data set upon which we can build to test more complex and time-dependent scattering phenomena, such as extreme scattering events.