Scatter broadening measurements of 124 pulsars at 327 MHz

TL;DR

This study measures scatter broadening times for 124 pulsars at 327 MHz, expanding the dataset and analyzing the interstellar medium's turbulence spectrum up to 3 kpc, confirming Kolmogorov turbulence within this range.

Contribution

It provides new scatter broadening measurements for 58 pulsars, increasing the existing data by 40%, and analyzes the interstellar medium's turbulence spectrum using these measurements.

Findings

Scatter broadening times increase with dispersion measure.

Interstellar medium turbulence follows Kolmogorov spectrum up to 3 kpc.

Deviations from Kolmogorov spectrum observed beyond 3 kpc.

Abstract

We present the measurements of scatter broadening time-scales ($\tau_{sc}$) for 124 pulsars at 327 MHz, using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37 $-$ 503 pc cm$^{-3}$ and declination ($\delta$) range of $-$57$^{\circ} < \delta< 60^{\circ}$. New $\tau_{sc}$ estimates for 58 pulsars are presented, increasing the sample of all such measurements by about 40% at 327 MHz. Using all available $\tau_{sc}$ measurements in the literature, we investigate the dependence of $\tau_{sc}$ on dispersion measure. Our measurements, together with previously reported values for $\tau_{sc}$, affirm that the ionized interstellar medium upto 3 kpc is consistent with Kolmogorov spectrum, while it deviates significantly beyond this distance.