Exploiting Network Topology for Accelerated Bayesian Inference of Grain Surface Reaction Networks

The Astrophysical Journal, vol. 904, pp. 197

Abstract

Abstract In the study of grain-surface chemistry in the interstellar medium, there exists much uncertainty regarding the reaction mechanisms with few constraints on the abundances of grain-surface molecules. Bayesian inference can be performed to determine the likely reaction rates. In this work, we consider methods for reducing the computational expense of performing Bayesian inference on a reaction network by looking at the geometry of the network. Two methods of exploiting the topology of the reaction network are presented. One involves reducing a reaction network to just the reaction chains with constraints on them. After this, new constraints are added to the reaction network and it is shown that one can separate this new reaction network into subnetworks. The fact that networks can be separated into subnetworks is particularly important for the reaction networks of interstellar complex-organic molecules, whose surface reaction networks may have hundreds of reactions. Both methods allow the maximum-posterior reaction rate to be recovered with minimal bias.

Authors 4

1. Johannes Heyl corresponding

   University College London

   Affiliation as printed

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK; johannes.heyl.19@ucl.ac.uk

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK

2. S. Viti Aachen Leiden Observatory

   Leiden University · Leiden Observatory · University College London

   Affiliation as printed

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK; johannes.heyl.19@ucl.ac.uk

   Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK

3. Jonathan Holdship Aachen Leiden Observatory

   Leiden University · Leiden Observatory · University College London

   Affiliation as printed

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK; johannes.heyl.19@ucl.ac.uk

   Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden, The Netherlands

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK

4. Stephen M. Feeney

   University College London

   Affiliation as printed

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK; johannes.heyl.19@ucl.ac.uk

   Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK