%AWalmsley, Mike [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%AWalmsley, Mike [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%ASmith, Lewis [Oxford Computer Science, University of Oxford, 15 Parks Rd, Oxford OX1 3QD, UK]%ASmith, Lewis [Oxford Computer Science, University of Oxford, 15 Parks Rd, Oxford OX1 3QD, UK]%ALintott, Chris [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%ALintott, Chris [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%AGal, Yarin [Oxford Computer Science, University of Oxford, 15 Parks Rd, Oxford OX1 3QD, UK]%AGal, Yarin [Oxford Computer Science, University of Oxford, 15 Parks Rd, Oxford OX1 3QD, UK]%ABamford, Steven [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK]%ABamford, Steven [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK]%ADickinson, Hugh [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%ADickinson, Hugh [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%AFortson, Lucy [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%AFortson, Lucy [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%AKruk, Sandor [European Space Agency, ESTEC, Keplerlaan 1, NL-2201 AZ Noordwijk, the Netherlands]%AKruk, Sandor [European Space Agency, ESTEC, Keplerlaan 1, NL-2201 AZ Noordwijk, the Netherlands]%AMasters, Karen [Haverford College, Department of Physics and Astronomy, 370 Lancaster Avenue, Haverford, PA 19041, USA, Institute for Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX, UK]%AMasters, Karen [Haverford College, Department of Physics and Astronomy, 370 Lancaster Avenue, Haverford, PA 19041, USA, Institute for Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX, UK]%AScarlata, Claudia [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%AScarlata, Claudia [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%ASimmons, Brooke [Physics Department, Lancaster University, Lancaster LA1 4YB, UK, Center for Astrophysics and Space Sciences (CASS), Department of Physics, University of California, San Diego, CA 92093, USA]%ASimmons, Brooke [Physics Department, Lancaster University, Lancaster LA1 4YB, UK, Center for Astrophysics and Space Sciences (CASS), Department of Physics, University of California, San Diego, CA 92093, USA]%ASmethurst, Rebecca [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%ASmethurst, Rebecca [Oxford Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK]%AWright, Darryl [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%AWright, Darryl [School of Physics and Astronomy, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, USA, Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA]%BJournal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 491; Journal Issue: 2; Related Information: CHORUS Timestamp: 2020-10-06 20:05:25 %D2019%IOxford University Press %JJournal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 491; Journal Issue: 2; Related Information: CHORUS Timestamp: 2020-10-06 20:05:25 %K %MOSTI ID: 10125608 %PMedium: X %TGalaxy Zoo: probabilistic morphology through Bayesian CNNs and active learning %XABSTRACT

We use Bayesian convolutional neural networks and a novel generative model of Galaxy Zoo volunteer responses to infer posteriors for the visual morphology of galaxies. Bayesian CNN can learn from galaxy images with uncertain labels and then, for previously unlabelled galaxies, predict the probability of each possible label. Our posteriors are well-calibrated (e.g. for predicting bars, we achieve coverage errors of 11.8 per cent within a vote fraction deviation of 0.2) and hence are reliable for practical use. Further, using our posteriors, we apply the active learning strategy BALD to request volunteer responses for the subset of galaxies which, if labelled, would be most informative for training our network. We show that training our Bayesian CNNs using active learning requires up to 35–60 per cent fewer labelled galaxies, depending on the morphological feature being classified. By combining human and machine intelligence, Galaxy zoo will be able to classify surveys of any conceivable scale on a time-scale of weeks, providing massive and detailed morphology catalogues to support research into galaxy evolution.

%0Journal Article