Representation learning for fast radio burst dynamic spectra

Monthly Notices of the Royal Astronomical Society, vol. 538, pp. 408–425

Abstract

ABSTRACT Fast radio bursts (FRBs) are millisecond-duration radio transients of extragalactic origin, with diverse time-frequency patterns and emission properties that require explanation. With one possible exception, FRBs are detected only in the radio, analysing their dynamic spectra is therefore crucial to disentangling the physical processes governing their generation and propagation. Furthermore, comparing FRB morphologies provides insights into possible differences among their progenitors and environments. This study applies unsupervized learning and deep-learning techniques to investigate FRB dynamic spectra, focusing on two approaches: principal component analysis (PCA) and a convolutional auto-encoder (CAE) enhanced by an information-ordered bottleneck (IOB) layer. PCA served as a computationally efficient baseline, capturing broad trends, identifying outliers, and providing valuable insights into large data sets. However, its linear nature limited its ability to reconstruct complex FRB structures. In contrast, the IOB-augmented CAE excelled at capturing intricate features, with high reconstruction accuracy and effective denoizing at modest signal-to-noise ratios. The IOB layer’s ability to prioritize relevant features enabled efficient data compression, preserving key morphological characteristics with minimal latent variables. When applied to real FRBs from Canadian Hydrogen Intensity Mapping Experiment (CHIME), the IOB–CAE generalized effectively, revealing a latent space that highlighted the continuum of FRB morphologies and the potential for distinguishing intrinsic differences between burst types. This framework demonstrates that while FRBs may not naturally cluster into discrete groups, advanced representation learning techniques can uncover meaningful structures, offering new insights into the diversity and origins of these bursts.

Authors 4

1. Dirk Kuiper corresponding

   University of Amsterdam

   Affiliation as printed

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam ,

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam, The

2. Gabriella Contardo

   Scuola Internazionale Superiore di Studi Avanzati · University of Nova Gorica

   Affiliation as printed

   Center for Astrophysics and Cosmology, University of Nova Gorica , Vipavska 11c, SI-5270 Ajdovščina ,

   Theoretical and Scientific Data Science, Scuola Internazionale Superiore di Studi Avanzati (SISSA) , Via Bonomea, 265, I-34136 Trieste TS ,

   Center for Astrophysics and Cosmology, University of Nova Gorica , Vipavska 11c, SI-5270 Ajdovščina,

   Theoretical and Scientific Data Science, Scuola Internazionale Superiore di Studi Avanzati (SISSA) , Via Bonomea, 265, 34136 Trieste TS,

3. Daniela Huppenkothen Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands · University of Amsterdam

   Affiliation as printed

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam ,

   SRON Netherlands Institute for Space Research , Niels Bohrlaan 4, NL-2333CA Leiden ,

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam, The

   SRON Netherlands Institute for Space Research , Niels Bohrlaan 4, 2333CA Leiden, The

4. Jason W. T. Hessels

   Trottier Space Institute at McGill · McGill University · University of Amsterdam · Netherlands Institute for Radio Astronomy

   Affiliation as printed

   ASTRON, Netherlands Institute for Radio Astronomy , Oude Hoogeveensedijk 4, NL-7991 PD Dwingeloo ,

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam ,

   Department of Physics, McGill University , 3600 rue University, Montréal, QC H3A 2T8 ,

   Trottier Space Institute, McGill University , 3550 rue University, Montréal, QC H3A 2A7 ,

   ASTRON, Netherlands Institute for Radio Astronomy , Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The

   Anton Pannekoek Institute for Astronomy, University of Amsterdam , Science Park 904, NL-1098 XH Amsterdam, The

   Department of Physics, McGill University, 3600 rue University, Montréal , QC H3A 2T8,

   Trottier Space Institute, McGill University , 3550 rue University, Montréal, QC H3A 2A7,