Masao Sako

Masao Sako
Standing Faculty

Professor and Undergraduate Chair

Research Areas: Observational Astronomy and Cosmology



           2020-present - Professor, University of Pennsylvania      

           2012-2020 - Associate Professor, University of Pennsylvania

           2006-2012 - Assistant Professor, University of Pennsylvania

  • 2003 – 2006 — KIPAC Postdoctoral Research Fellow, Stanford University
  • 2001 – 2003 — Chandra Postdoctoral Fellow, California Institute of Technology
  • 1997 – 2001 — Graduate Research Assistant, Columbia Un

2001 — Ph. D., Graduate School of Arts and Sciences, Columbia University
2000 — M. Phil., Graduate School of Arts and Sciences, Columbia University
1999 — M. A., Graduate School of Arts and Sciences, Columbia University
1995 — B. S., Fu Foundation School of Engineering and Applied Science, Columbia University

Research Interests

My research focuses on observational cosmology with supernovae (SNe). Measurements of luminosity distances to Type Ia SNe have shown that our Universe is dominated by an unknown component called dark energy, which is causing the expansion of the Universe to accelerate. My group is involved in current (DES) and future (LSST, Roman) large-scale optical surveys that will discover thousands of SNe that will be used to map out the detailed expansion history of the Universe.

My group is actively involved in developing machine learning and deep learning methods, which are replacing and superceding many traditional data analysis methods in astronomy and cosmology.  We are also investigating the use of GPUs for image analyses.

Selected Publications

"SCONE: Supernova Classification with a Convolutional Neural Network", Qu, H., Sako, M., Moller, A., & Doux, C., The Astronomical Journal, Volume 162, Issue 2, id.67 (2021)

"Trans-Neptunian Objects Found in the First Four Years of the Dark Energy Survey", Bernardinelli, P. H., Bernstein, G. M., Sako, M., Liu, T., Saunders, W. R., Khain, T., Lin, H. W., Gerdes, D. W., et al., The Astrophysical Journal Supplement Series, Volume 247, Issue 1, id.32,247 (2020)

"First Cosmology Results Using SNe Ia from the Dark Energy Survey: Analysis, Systematic Uncertainties, and Validation", Brout, D., Scolnic, D., Kessler, R., D'Andrea, C. B., Davis, T. M., Gupta, R. R., Hinton, S. R., Kim, A. G., et al., The Astrophysical Journal, Volume 874, Issue 2, article id. 150 (2019)

"First Cosmology Results using Type Ia Supernovae from the Dark Energy Survey: Constraints on Cosmological Parameters", Abbott, T. M. C., Allam, S., Andersen, P., Angus, C., Asorey, J., Avelino, A., Avila, S., Bassett, B. A., et al., The Astrophysical Journal Letters, Volume 872, Issue 2, article id. L30 (2019)

"First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814", Soares-Santos, M., Palmese, A., Hartley, W., Annis, J., Garcia-Bellido, J., Lahav, O., Doctor, Z., Fishbach, M., et al., The Astrophysical Journal Letters, Volume 876, Issue 1, article id. L7 (2019)

"The Data Release of the Sloan Digital Sky Survey-II Supernova Survey", Sako, M., Bassett, B., Becker, A. C., Brown, P. J., Campbell, H., Wolf, R., Cinabro, D., D'Andrea, C. B., et al., Publications of the Astronomical Society of the Pacific, Volume 130, Issue 988, pp. 064002 (2018)