Identifying Physical Structures in Our Galaxy with Gaussian Mixture Models: An Unsupervised Machine Learning Technique

The Astrophysical Journal, vol. 958, pp. 136

Abstract

Abstract We explore the potential of the Gaussian mixture model (GMM), an unsupervised machine-learning method, to identify coherent physical structures in the interstellar medium. The implementation we present can be used on any kind of spatially and spectrally resolved data set. We provide a step-by-step guide to use these models on different sources and data sets. Following the guide, we run the models on NGC 1977, RCW 120, and RCW 49 using the [C ii] 158 μm mapping observations from the SOFIA telescope. We find that the models identified six, four, and five velocity coherent physical structures in NGC 1977, RCW 120, and RCW 49, respectively, which are validated by analyzing the observed spectra toward these structures and by comparison to earlier findings. In this work we demonstrate that GMM is a powerful tool that can better automate the process of spatial and spectral analysis to interpret mapping observations.

Authors 17

1. M. Tiwari corresponding

   Max Planck Institute for Radio Astronomy · University of Maryland, College Park

   Affiliation as printed

   Max Planck Institute for Radioastronomy, Auf dem Hügel, D-53121 Bonn, Germany

   University of Maryland, Department of Astronomy, College Park, MD 20742-2421, USA

2. Rens Kievit Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

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

3. S. Kabanovic

   University of Cologne

   Affiliation as printed

   I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

4. Lars Bonne

   Ames Research Center

   Affiliation as printed

   SOFIA Science Center, USRA, NASA Ames Research Center, M.S. N232-12, Moffett Field, CA 94035, USA

5. Fabrizio Falasca

   Courant Institute of Mathematical Sciences · New York University

   Affiliation as printed

   Courant Institute of Mathematical Sciences, New York University, New York, NY, USA

6. C. Guevara

   University of Cologne

   Affiliation as printed

   I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

7. R. Higgins

   University of Cologne

   Affiliation as printed

   I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

8. M. Justen

   University of Cologne

   Affiliation as printed

   I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

9. R. Karim

   University of Maryland, College Park

   Affiliation as printed

   University of Maryland, Department of Astronomy, College Park, MD 20742-2421, USA

10. Ü. Kavak

    Ames Research Center

    Affiliation as printed

    SOFIA Science Center, USRA, NASA Ames Research Center, M.S. N232-12, Moffett Field, CA 94035, USA

11. C. H. M. Pabst Aachen Leiden Observatory

    Leiden University · Instituto de Física Fundamental · Leiden Observatory

    Affiliation as printed

    Instituto de Física Fundamental, CSIC, Calle Serrano 121-123, E-28006 Madrid, Spain

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

12. Marc W. Pound

    University of Maryland, College Park

    Affiliation as printed

    University of Maryland, Department of Astronomy, College Park, MD 20742-2421, USA

13. Nicola Schneider

    University of Cologne

    Affiliation as printed

    I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

14. Robert Simon

    University of Cologne

    Affiliation as printed

    I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

15. JÜRGEN STUTZKI

    University of Cologne

    Affiliation as printed

    I. Physik. Institut, University of Cologne, Zülpicher Str. 77, D-50937 Cologne, Germany

16. M. G. Wolfire

    University of Maryland, College Park

    Affiliation as printed

    University of Maryland, Department of Astronomy, College Park, MD 20742-2421, USA

17. Alexander G. G. M. Tielens Aachen Leiden Observatory

    Leiden University · Leiden Observatory · University of Maryland, College Park

    Affiliation as printed

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

    University of Maryland, Department of Astronomy, College Park, MD 20742-2421, USA