Radio galaxy zoo: Unsupervised clustering of convolutionally auto-encoded radio-astronomical images

Publications of the Astronomical Society of the Pacific IOP Publishing 131:1004 (2019) 108011

Authors:

Nicholas O Ralph, Ray P Norris, Gu Fang, Laurence AF Park, Timothy J Galvin, Matthew J Alger, Heinz Andernach, Christopher Lintott, Lawrence Rudnick, Stanislav Shabala, O Ivy Wong

Abstract:

This paper demonstrates a novel and efficient unsupervised clustering method with the combination of a self-organizing map (SOM) and a convolutional autoencoder. The rapidly increasing volume of radio-astronomical data has increased demand for machine-learning methods as solutions to classification and outlier detection. Major astronomical discoveries are unplanned and found in the unexpected, making unsupervised machine learning highly desirable by operating without assumptions and labeled training data. Our approach shows SOM training time is drastically reduced and high-level features can be clustered by training on auto-encoded feature vectors instead of raw images. Our results demonstrate this method is capable of accurately separating outliers on a SOM with neighborhood similarity and K-means clustering of radio-astronomical features. We present this method as a powerful new approach to data exploration by providing a detailed understanding of the morphology and relationships of Radio Galaxy Zoo (RGZ) data set image features which can be applied to new radio survey data.

The tidal disruption event AT2017eqx: spectroscopic evolution from hydrogen rich to poor suggests an atmosphere and outflow

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 488:2 (2019) 1878-1893

Authors:

M Nicholl, PK Blanchard, E Berger, S Gomez, R Margutti, KD Alexander, J Guillochon, J Leja, R Chornock, B Snios, K Auchettl, AG Bruce, P Challis, DJ D’Orazio, MR Drout, T Eftekhari, RJ Foley, O Graur, CD Kilpatrick, A Lawrence, AL Piro, C Rojas-Bravo, NP Ross, P Short, SJ Smartt, KW Smith, B Stalder

Unravelling the origin of the counter-rotating core in IC 1459 with KMOS and MUSE

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 488:2 (2019) 1679-1694

Authors:

Laura J Prichard, Sam P Vaughan, Roger L Davies

Nine-hour X-ray quasi-periodic eruptions from a low-mass black hole galactic nucleus

(2019)

Authors:

G Miniutti, RD Saxton, M Giustini, KD Alexander, RP Fender, I Heywood, I Monageng, M Coriat, AK Tzioumis, AM Read, C Knigge, P Gandhi, ML Pretorius, B Agís-González

SN2018kzr: a rapidly declining transient from the destruction of a white dwarf

(2019)

Authors:

Owen R McBrien, Stephen J Smartt, Ting-Wan Chen, Cosimo Inserra, James H Gillanders, Stuart A Sim, Anders Jerkstrand, Armin Rest, Stefano Valenti, Rupak Roy, Mariusz Gromadzki, Stefan Taubenberger, Andreas Flörs, Mark E Huber, Ken C Chambers, Avishay Gal-Yam, David R Young, Matt Nicholl, Erkki Kankare, Ken W Smith, Kate Maguire, Ilya Mandel, Simon Prentice, Ósmar Rodríguez, Jonathon Pineda Garcia, Claudia P Gutiérrez, Lluís Galbany, Cristina Barbarino, Peter SJ Clark, Jesper Sollerman, Shrinivas R Kulkarni, Kishalay De, David AH Buckley, Arne Rau