The analysis of the largest sample of multi-frequency pulsar scatter time estimates

TL;DR

This study analyzes pulse broadening times across multiple frequencies for 60 pulsars, revising existing models of scattering behavior and revealing that scatter time scaling varies with dispersion measure, especially at high DMs.

Contribution

It provides the largest multi-frequency pulsar scatter time database, revises the relation between spectral slope and dispersion measure, and offers new estimates of scattering at 1 GHz.

Findings

Deviation from theoretical spectral slope predictions across all DMs

Almost constant DM-averaged spectral slope with high DM exceptions

Flatter relation between scatter time and DM at 1 GHz

Abstract

We present our results of pulse broadening time estimates and the study of the frequency scaling of this quantity for 60 pulsars based on actual multi-frequency scattering estimates. This research was based on our own measurements, performed on the observational data and the profiles from various pulsar profile databases, as well as the scatter time measurements that were found in the literature. We were able to construct a database of over 60 pulsars with true multi-frequency $\alpha$ measurements, which allowed us to revise the previously proposed relations between the scatter time spectral slope and the dispersion measure (DM). We found that the deviations from theoretical predictions of the value of $\alpha$ appear for pulsars regardless of their DM, however the DM-averaged value of the scaling index is almost constant except for pulsars with very high DMs. Based on the obtained slopes we were also able to estimate the amount of scattering at the standard frequency of 1 GHz. We found that while the estimated standardized pulse broadening time increases with DM the relation seems to be much flatter than it was previously proposed, which suggests higher values of the scatter time for mid-DM pulsars, and lower values of expected pulse broadening for highly dispersed sources.