DirectDedispersion.jl

Direct dedispersion, in Julia.

This package implements the direct dedispersion algorithm in pure Julia. Quoting from Barsdell et al. (2012):

The direct dedispersion algorithm operates by directly summing frequency channels along a quadratic dispersion trail for each time sample and dispersion measure. In detail, the algorithm computes an array of dedispersed time series $D$ from an input data set $A$ according to the following equation: $$\boxed{D_{d, t} = \sum_{\nu}^{N_{\nu}} A_{\nu, t + \Delta t(d, \nu)}}$$ where the subscripts $d$, $t$ and $\nu$ represent dispersion measure, time sample and frequency channel, respectively, and $N_{\nu}$ is the total number of frequency channels.

Install it by typing and running:

] add DirecDedispersion

in the Julia REPL.

Here is an example of the same time series, obtained via PRESTO and via DirectDedispersion.jl, from 30 seconds of data with a simulated FRB. The FRB has a DM of 1000 pc cm$^{-3}$, and an arrival time of 15 seconds¹:

The simulation was carried out using the simulateSearch library, and is included in this package as a part of its testing suite here.