AN ACCURATE AND EFFICIENT ALGORITHM FOR DETECTION OF RADIO BURSTS WITH AN UNKNOWN DISPERSION MEASURE, FOR SINGLE-DISH TELESCOPES AND INTERFEROMETERS

ABSTRACT Astronomical radio signals are subjected to phase dispersion while traveling through the interstellar medium. To optimally detect a short-duration signal within a frequency band, we have to precisely compensate for the unknown pulse dispersion, which is a computationally demanding task. We...

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Vydané v:The Astrophysical journal Ročník 835; číslo 1; s. 11 - 23
Hlavní autori: Zackay, Barak, Ofek, Eran O.
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Philadelphia The American Astronomical Society 20.01.2017
IOP Publishing
Predmet:
ALGORITHMS
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Bins
CALCULATION METHODS
Complexity
Convolution
DATA ANALYSIS
Data transmission
DETECTION
Dispersion
DISPERSIONS
Fast Fourier transformations
FOURIER TRANSFORMATION
Fourier transforms
Frequencies
Galling
Graphics processing units
High level languages
INTERFEROMETERS
Interstellar matter
Interstellar medium
methods: data analysis
methods: statistical
Optimization
Personal computers
Programming languages
Radio bursts
Radio interferometers
Radio signals
Radio telescopes
Searching
SENSITIVITY
TELESCOPES
TWO-DIMENSIONAL CALCULATIONS
ISSN:0004-637X, 1538-4357
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Popis
Shrnutí:ABSTRACT Astronomical radio signals are subjected to phase dispersion while traveling through the interstellar medium. To optimally detect a short-duration signal within a frequency band, we have to precisely compensate for the unknown pulse dispersion, which is a computationally demanding task. We present the "fast dispersion measure transform" algorithm for optimal detection of such signals. Our algorithm has a low theoretical complexity of , where Nf, Nt, and NΔ are the numbers of frequency bins, time bins, and dispersion measure bins, respectively. Unlike previously suggested fast algorithms, our algorithm conserves the sensitivity of brute-force dedispersion. Our tests indicate that this algorithm, running on a standard desktop computer and implemented in a high-level programming language, is already faster than the state-of-the-art dedispersion codes running on graphical processing units (GPUs). We also present a variant of the algorithm that can be efficiently implemented on GPUs. The latter algorithm's computation and data-transport requirements are similar to those of a two-dimensional fast Fourier transform, indicating that incoherent dedispersion can now be considered a nonissue while planning future surveys. We further present a fast algorithm for sensitive detection of pulses shorter than the dispersive smearing limits of incoherent dedispersion. In typical cases, this algorithm is orders of magnitude faster than enumerating dispersion measures and coherently dedispersing by convolution. We analyze the computational complexity of pulsed signal searches by radio interferometers. We conclude that, using our suggested algorithms, maximally sensitive blind searches for dispersed pulses are feasible using existing facilities. We provide an implementation of these algorithms in Python and MATLAB.
Bibliografia:ApJ97140
Instrumentation, Software, Laboratory Astrophysics, and Data
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 14
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/835/1/11