James Taylor

James Taylor
Associate Professor, Undergraduate Advisor - Physics & Astronomy
Location: PHY 256
Phone: 519-888-4567 x48115


Dr. Taylor is using whatever tools he can, including numerical simulations, astrophysical theory and observational data, to try to figure what dark matter is, where it is, and how it behaves. His research includes gravitational lensing and dynamical studies of galaxy clusters, the properties of the smallest galaxies in the local universe, and the theory behind dark matter halos around galaxies and clusters.

Research Interests

  • Dark matter
  • Cosmological structure formation
  • Galaxy formation
  • Galaxy dynamics
  • Galaxy clusters
  • Massive black holes
  • Cosmology
  • Computational & theoretical astrophysics
  • Astrophysics and Gravitation

Scholarly Research

Numerical Simulations of Dark Halos: One of the ways we can learn about dark matter is by modelling how it should behave using numerical simulations. With the resources of SHARCNET, Ontario’s local supercomputing network, as well as machines in California, Germany and Australia, Dr. Taylor has been studying how cosmology - the large-scale properties of the universe - affects the abundance, shape and smoothness of dense structures like galaxy clusters. Observational Tests of Dark Matter: There are three main ways of studying dark matter observationally: galaxy dynamics, gravitational lensing, and direct or indirect detection of dark matter particles. Dr, Taylor is currently involved in several large surveys that provide dynamical and lensing data, and has previously worked on predictions for astro-particle experiments that search for the dark matter candidate particle (“direct detection”), or other particles it produces or interacts with. Galaxy Dynamics and Galaxy Surveys: COSMOS provides a very rich data-set of galaxies imaged at many different wavelengths. Dr. Taylor searches through this field for small, nearby galaxies that trace the dark matter distribution on the smallest scales. The relative abundance of these galaxies may tell us whether dark matter is genuinely “cold” (and thus lumpy on small scales) or whether it is “warm” (and thus fluffy on small scales).

Industrial Research

member, International Astronomical Union, member, Canadian Astronomical Society, ​member, American Astronomical Society


  • 2001 Ph. D. (Astronomy), University of Victoria, Canada
  • 1994 M. Sc. (Astronomy), University of Toronto, Canada
  • 1993 B. Sc. (Mathematics & Physics), University of Toronto, Canada


  • 2009–2014: NSERC Discovery Grant
  • 2006–2009: NSERC Discovery Grant
  • 2006–2007: Co-Investigator, Hubble Space Telescope Cycle 15 Snapshot Proposal #10881 (143 orbits)

Professional Associations

  • Member, International Astronomical Union
  • Member, Canadian Astronomical Society
  • Member, American Astronomical Society

Affiliations and Volunteer Work

  • Waterloo Centre for Astrophysics
  • Affiliate, Perimeter Institute for Theoretical Physics


  • PHYS 236 - Computational Physics 1
    • Taught in 2019, 2020, 2021
  • PHYS 249 - Computational Physics and Linear Algebra
    • Taught in 2022, 2023
  • PHYS 364 - Mathematical Physics 1
    • Taught in 2020, 2021
  • PHYS 781 - Fundamentals of Astrophysics
    • Taught in 2019, 2023
  • PHYS 787 - Cosmology
    • Taught in 2023

* Only courses taught in the past 5 years are displayed.

Selected/Recent Publications

  • What Do Dark Matter Halo Properties Tell Us about Their Mass Assembly Histories? Wong, Anson W.C., Taylor, James E. 2012 ApJ 757, 102
  • The Next Generation Virgo Cluster Survey (NGVS). I. Introduction to the Survey, Ferrarese et al. 2012 ApJS, 200, 4
  • COSMOS: Stochastic Bias from Measurements of Weak Lensing and Galaxy Clustering, Jullo, E., Rhodes, J., Kiessling, A., Taylor, J. E., Massey, R., Berge, J., Schimd, C., Kneib, J.-P., Scoville, N. 2012 ApJ 750, 37
  • Measuring the Geometry of the Universe from Weak Gravitational Lensing behind Galaxy Groups in the HST COSMOS Survey Taylor, J. E., Massey, R. J., Leauthaud, A., George, M. R., Rhodes, J., Kitching, T. D., Capak, P., Ellis, R., Finoguenov, A., Ilbert, O., Jullo, E., Kneib, J.-P., Koekemoer, A. M., Scoville, N., Tanaka, M., 2012 ApJ 749, 127
  • New constraints on the evolution of the stellar-to-dark matter connection: a combined analysis of galaxy-galaxy lensing, clustering, and stellar mass functions from z=0.2 to z=1 Leauthaud, A., Tinker, J., Bundy, K., Behroozi, P. S., Massey, R., Rhodes, J., George, M. R., Kneib, J.-P., Benson, A., Wechsler, R. H., Busha, M. T., Capak, P., Cortes, M., Ilbert, O., Koekemoer, A. M., Le Fevre, O., Lilly, S., McCracken, H. J., Salvato, M., Schrabback, T., Scoville, N., Smith, T., Taylor, J. E., ApJ in press (preprint arXiv:1104.0928)
  • The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). I: The UV luminosity function of the central 12 square degrees A. Boselli et al. 2011 A&A 528, 107
  • Please see Dr. Taylor's website for a complete list of his publications.