Roy David Williams

roy at roe.ac.uk

My work now focuses on providing people with meaningful access to scientific and technical data, as well as learning from, making decisions from, and preserving that data.

My career began with a degree in mathematics from Cambridge, then a PhD in nuclear physics and mathematical physics at Caltech. I was proud to work with Nobel-prizewinner Willy Fowler (paper), and I think my co-workers and I were first to work on nuclear pasta (paper).

I worked in physics a few more years, then worked with the new architecture computers, rebuilding scientific simulation codes for parallel machines, and making new codes with unstructured meshes and dynamic load balancing (see 1993 below). I was co-author of a book Parallel Computing Works!. There was a lot of fluid-flow simulation on parallel computers, inculuding a simulation of the hypersonic flow around the Huygens space probe that landed on Saturn's moon Titan (paper).

The world-wide web arrived in the early 1990's, where I was an early adopter. In 1995, I gave a lecture and wrote an article about its potential. I was building web applications in 1996, delivering Earth remote-sensing data over the internet, where I wrote about what I called Hypermaps, a prequel to Google Maps.

I worked with the LIGO (gravitational waves) project in the late 1990's, introducing them to databases and XML, and built science gateways for the US Teragrid project. I was with the Virtual Observatory from the start, as architect, also creating in large part the VOTable and VOEvent standards, now widely used. There was a lot of work on astronomical transients, leading up to the Palomar Transient Factory and preliminary work on LSST, realizing that soon the transient detections would overwhelm the ability of telescopes to observe them all. I worked again for the LIGO group from 2010, developing the Gravitational Wave Open Science Center. I was lucky enough to be at Caltech when the first detection happened, with all its excitement. In June 2017 I moved to Edinburgh, where I work at the Royal Observatory, where I work in preparation for the flood of transient observations from the Rubin Observatory telescope, being commissioned in 2025. There are expected to be millions of transient observations per night, and we are preparing by building a prototype called Lasair at lasair.lsst.ac.uk. Edinburgh is a great place to live!

Memoir

written 2020 - 2025:
  • Computing As A Sport
    (also available in print).
  • Science, engineering, computer science, and personal anecdotes from a career with computers.
  • Astronomy, gravitational waves, and black holes
  • Nuclear physics of the Sun and supernovae
  • Early internet, social media, and citizen science
  • Science with children
  • Deep Time, Deep Space, and Deep Data
  • Cambridge, Caltech, Oxford, and Edinburgh

    Playthings

    Paintings 2019 and beyond

    Stellations of the Icosahedron

    Furniture

    Stained glass

    Javascript games.

    Useless information about Pi

    Xmorphia: beautiful equations

    Paintings of Vermeer: ancient pages from 1995

    Greatstreets: 47 city street plans to scale

    Academia

    2025

    A systematically-selected sample of luminous, long-duration, ambiguous nuclear transients
    P. Wiseman, R. D. Williams, et al
    Click for MNRAS 537 (2) 2024–2045 or arxiv 2406.11552.

    2024

    Lasair The Movie (video)
    Roy Williams
    Click for youtube.
    Enabling Science from the Rubin Alert Stream with Lasair
    Roy D. Williams, Gareth P. Francis, Andy Lawrence, Terence M. Sloan, Stephen J. Smartt, Ken W. Smith, David R. Young
    Click for RAS Techniques and Instruments, 3(1) 362–371 or arxiv 2404.08315.

    2023

    NEural Engine for Discovering Luminous Events (NEEDLE): identifying rare transient candidates in real time from host galaxy images
    X. Sheng et. al.
    MNRAS 531(2) 2474–2492 or arxiv 2312.04968.

    GW190425: Pan-STARRS and ATLAS coverage of the skymap and limits on optical emission associated with FRB190425
    S. J. Smartt et. al.
    MNRAS 528, 2299–2307 (2024) or arxiv 2309.11340.

    Fitting Early light curves of Explosive Astrophysics
    R. D. Williams
    Click for pdf.

    2019

    Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo Abbott et. al. (LIGO collaboration)
    submitted to Nature Scientific Data Click for Arxiv and pdf.

    Lasair: The Transient Alert Broker for LSST:UK Ken Smith, Roy D. Williams, D. R. Young, A. Ibsen, S. J. Smartt, A. Lawrence, D. Morris, S. Voutsinas, and M. Nicholl
    Research Notes of the AAS, Volume 3, Number 1 Click here.

    2017

    GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
    LIGO Scientific Consortium
    Phys. Rev. Lett. 119, 161101.

    2016

    Observation of Gravitational Waves from a Binary Black Hole Merger
    LIGO Scientific Consortium
    Phys. Rev. Lett. 116, 061102

    2013

    LIGO Open Science Center: data releases from the LIGO project.
    http://losc.ligo.org. 2013 - present.

    LIGO Data Management Plan Stuart Anderson and Roy Williams, 2013
    Click here.

    2012

    Responding to the Event Deluge Roy D. Williams, Scott D. Barthelmy, Robert B. Denny, Matthew J. Graham, John Swinbank
    Proceedings of SPIE Observatory Operations, Amsterdam, 2012 Click here.

    Community Input for LIGO Open Data edited by Roy Williams, Christian Ott, Steve Groom, 2012
    Click here.

    Astronomy with Cutting-Edge ICT: From Transients in the Sky to Data over the Continents (India-US) Ashish Mahabal, Ajit Kembhavi, Roy Williams and Sharmad Navelkar
    Click here.

    2011

    Gravitational Waves and Time-Domain Astronomy Joan Centrella, Samaya Nissanke and Roy Williams
    Proceedings of the International Astronomical Union / Volume 7 / Symposium S285 / September 2011, pp 191-198 Click here.

    Using the VO to Study the Time Domain Rob Seaman, Roy Williams, Matthew Graham and Tara Murphy
    Proceedings of the International Astronomical Union / Volume 7 / Symposium S285 / September 2011, pp 221 - 226
    Click here.

    2009

    Skyalert: authoring, dissemination, annotating, mining, and messaging of immediate astronomical events. 2009 - 2013.

    Sky Event Reporting Metadata (VOEvent)
    R. Seaman, R.D. Williams, A. Allan, S. Barthelmy, J. Bloom, M. Graham, F. Hessman, S. Marka, A. Rots, C. Stoughton, T. Vestrand, R. White, P. Wozniak,
    A Recommendation of the International Virtual Observatory Alliance, 2006. HTML

    First Results from the Catalina Real-time Transient Survey
    A.J. Drake, S.G. Djorgovski, A. Mahabal, E. Beshore, S. Larson, M.J. Graham, R. Williams, E. Christensen, M. Catelan, A. Boattini, A. Gibbs, R. Hill, R. Kowalski, Astrophysical J. 696 (2009) 870. PDF

    2008

    National Virtual Observatory Summer School 2008
    Roy Williams, Faculty Chair
    Organized the content and teaching for a two-week intensive course on the Virtual Observatory, September 2008, Santa Fe, New Mexico.

    VIM: Visual Integration and Mining
    Integrate data from multiple positions and datasets.

    Skyalert: Real-time Astronomy for You and Your Robots
    R. D. Williams, S. G. Djorgovski, A. J. Drake, M. J. Graham, A. Mahabal.
    Proc. ADASS XVIII (2008), PASP, eds. D. Bohlender, P. Dowler and D. Durand link

    Describing Data and Data Collections in the VO
    Kent, B.R.; Hanisch, R.J.; Williams, R.D.
    in The National Virtual Observatory: Tools and Techniques for Astronomical Research, eds. Graham M.J., Fitzpatrick M.F., McGlynn T.A. ASP Conference Proceedings, vol. 382. PDF

    Data-Intensive Computing in the 21st Century Ian Gorton, Paul Greenfield, Alex Szalay, Roy Williams
    Computer 05/2008; DOI:10.1109/MC.2008.122 Click here.

    2007

    Transient Event Reporting and Response with VOEvent
    Seaman, R.; Allan, A.; Williams, R.
    Astronomical Data Analysis Software and Systems ASP Conference Series, Vol. 394, Eds R.W. Argyle, P.S. Bunclark, and J.R. Lewis., p.213 (2007) PDF

    The IVOA in 2007: Assessment and Future Roadmap
    Roy Williams and the IVOA Technical Coordination Group
    International Virtual Observatory Alliance, PDF

    Google Sky mashup
    Roy Williams and Andrew Drake
    Real-time display of events from multiple streams. 2007. (bring up the Google Earth/Sky client, click Current Sky Events and VOEventNet)., or click here.

    2006

    Astronomical network event and observation notification
    White R.R., Allan A., Barthelmy S., Bloom J., Graham M.J., Hessman F.V., Marka S., Rots A., Scholberg K., Seaman R., Stoughton C., Vestrand W.T., Williams R., Wozniak P.R.,
    Astronomische Nachrichten, 327 (2006) 775.

    Object detection in multi-epoch data
    G. Jogesh Babu, Ashish Mahabal, S. G. Djorgovski, R. Williams
    Statistical Methodology, Volume 5, Issue 4, p. 299-306. PDF

    The IVOA in 2006: Assessment and Future Roadmap
    Roy Williams and the IVOA Technical Coordination Group
    International Virtual Observatory Alliance, PDF.

    2005

    HotGrid: Graduated Access to Grid-Based Science Gateways
    Williams, R. Steenberg, C. Bunn, J. Lect. Notes Computer Sci. 3470 (2005) 78. PDF

    The IVOA in 2005: Assessment and Future Roadmap
    Roy Williams and the IVOA Technical Coordination Group
    International Virtual Observatory Alliance, PDF

    Virtual Observatory: From Concept to Implementation
    S. G. Djorgovski and R. Williams
    In: Science with Wavelengths on Human Scales, ASPCS, vol. 3xx. ASPCS PDF

    2004

    VOTable Format Definition
    Francois Ochsenbein, Roy Williams, Clive Davenhall, Daniel Durand, Pierre Fernique, David Giaretta, Robert Hanisch, Tom McGlynn, Alex Szalay, Mark B. Taylor, Andreas Wicenec,
    A Recommendation of the International Virtual Observatory Alliance. HTML

    An IVOA Standard for Unified Content Descriptors
    S. Derriere, N. Gray, R. Mann, A. Preite Martinez, J. McDowell, T. Mc Glynn, F. Ochsenbein, P. Osuna, G. Rixon, R.D. Williams.
    A Recommendation of the International Virtual Observatory Alliance. HTML

    2003

    Multi-Wavelength Image Space: Another Grid-Enabled Science
    Roy Williams, Bruce Berriman, Ewa Deelman, John Good, Joseph Jacob, Carl Kesselman, Carol Lonsdale, Seb Oliver, Tom Prince
    Concurrency & Computation, vol 15 (2003), pp 539-549. PDF,

    Grids and the Virtual Observatory
    Roy Williams
    in Grid Computing: Making The Global Infrastructure a Reality by Fran Berman, Anthony J.G. Hey, and Geoffrey Fox, Wiley, 2003, pp 837-858. PDF

    2002

    Scientific Data Mining Integration and Visualization
    Bob Mann, Roy Williams, Malcolm Atkinson, Ken Brodlie, Amos Storkey, Chris Williams,
    report of a workshop held in Edinburgh, 24-25 October 2002. PDF

    XML and Web Services for Astronomers
    Roy Williams and Robert Brunner
    tutorial at ADASS 2002, Baltimore, October 2002. PPT

    Network data analysis server (NDAS) prototype development
    Szabi Marka, Benoit Mours, Roy Williams
    Classical and Quantum Gravity 19 (7): 1537-1540 (2002)

    Agent based data management in digital libraries
    Y.Y. Yang, O.F. Rana, D. W. Walker, R. D. Williams
    Parallel Computing 28 (5): 773-792 (2002)

    2001

    Analysis of Shear Layers in a Fluid with Temperature-Dependent Viscosity
    D. J. Estep, S. M. Verduyn Lunel, and R. D. Williams
    J. Comp. Physics, vol 173 (2001), pp 17-60. PDF

    Web access to supercomputing
    G. Aloisio, M. Cafaro, C. Kesselman, R. Williams
    Computational Science and Engineering 3 (6): 66-72 (2001)

    A Virtual Data Grid for LIGO
    Ewa Deelman, Carl Kesselman, Roy Williams, Albert Lazzarini, Thomas A. Prince, Joe Romano and Bruce Allen
    Lecture Notes in Computer Science, vol 2110 (2001) pp 3-12
    PDF

    2000

    Estimating the Error of Numerical Solutions of Systems of Nonlinear Reaction-Diffusion Equations

    The Formation, Structure, and Stability of a Shear Layer in a Fluid with Temperature-Dependent Viscosity D. J. Estep, S. M. Verduyn Lunel, and R. D. Williams
    June 2000
    PDF.

    D. J. Estep, M. G. Larsen, and R. D. Williams
    Memoirs Amer. Math. Soc., 146 (2000) number 696, pp 1-109. PDF

    A Test Suite for High-Performance Parallel Java
     Jochem Hauser, Thorsten Ludewig, Roy Williams, Ralf Winkelmann, Torsten Gollnick, Sharon Brunett, Jean Muylaert
    Advances in Engineering Software 31 (8-9): 687-696 (2000)

    Grid computing on the web using the globus toolkit
    G. Aloisio G, M. Cafaro, P. Falabella, R. Williams
    Lecture Notes in Computer Science 1823: 32-40 (2000)

    Approaches to Federation of Astronomical Data
     Roy Williams
    in Virtual Observatories of the Future, eds. R. J. Brunner, S. G. Djorgovski, and A. S. Szalay, Astronomical Society of the Pacific, Conference Series 225. November 2000. PDF

    1999

    Special issue: Interfaces to Scientific Digital Archives
    ed. Roy Williams
    Future Generation Computer Systems 16 (1): VII-VIII (1999)

    The Digital Puglia Project: An active digital library of remote sensing data
    G. Aloisio, M. Cafaro, R. Williams
    Lecture Notes in Computer Science 1593: 563-572 (1999)

    An XML Architecture for High-Performance Web-Based Analysis of Remote-Sensing Archives
     Giovanni Aloisio, Giovanni Milillo, and Roy Williams
    Future Generation Computing Systems 16 (1): 91-100 NOV 1999. PDF.

    Strategies for Parallel and Numerical Scalability of CFD Codes
     Ralf Winkelmann, Jochem Hauser and Roy Williams
    Computational Methods in Applied Mechanical Engineering. 174 (3-4): 433-456 (1999). PDF
    (image shows Huygens craft, that landed on Titan Jan 2004)

    A Pure Java Parallel Flow Solver
     Jochem Hauser, Thorsten Ludewig, Torsten Gollnick, Ralf Winkelmann, Roy Williams, Jean Muylaert, and Martin Spel
    AIAA paper 99-0549, proceedings of 37th Aerospace Sciences Meeting, Reno NV, Jan 1999.
    PDF.

    XSIL: Extensible Scientific Interchange Language
     Kent Blackburn, Albert Lazzarini, Tom Prince and Roy Williams
    Lect. Notes. Comp. Sci. 1593 (1999) 513.
    PDF

    1998

    Report of the European Union - United States Workshop on Large Scientific Databases
    Roy Williams, Paul Messina, Fabrizio Gagliardi, John Darlington, and Giovanni Aloisio
    October 1999
    PDF.

    Interfaces to Scientific Data Archives
     Report of the NSF Workshop
     Roy Williams, Julian Bunn, Reagan Moore and James Pool,
    May 1998. HTML .

    Paraflow: A dataflow distributed data-computing system
    Roy Williams and Bruce Sears
    Lecture Notes in Computer Science 1401: 556-565 (1998)

    Metacomputing - From ideas to real implementations
    Wolfgang Nagel and Roy Williams
    Parallel Computing 24 (12-13): 1709-1711 (1998)

    1997

    A Distributed Web-based Metacomputing Environment
     G. Aloisio, M. Cafaro, P. Messina, R. D. Williams,
    in HPCN97, Vienna, April 1997. PDF

    A Tangled Web Strategy for Numerical and Parallel Scalability in Aerospace Simulation
     J. Haeuser, R. D. Williams and R. Winkelmann
    Proceedings of CFD97, University of Victoria, Canada, 25-27 May 1997. PDF.

    1996

    Dreaming of Hypermaps
    Caltech Engineering and Science magazine, PDF.

    Video: Letter R formed by evolution of non-uniform Gray-Scott model, 1999. Click here.

    Error Estimation for Numerical Differential Equations
    D. J. Estep, S. M. Verduyn Lunel and R. D. Williams
    IEEE Antennas and Propagation 38 (2): 71-76 (1996). PDF

    Accurate Parallel Integration of Large Sparse Systems of Differential Equations
     D. J. Estep and R. D. Williams
    Mathematical Models and Methods in Applied Sciences 6 (4): 535-568 (1996). PDF

    Efficient Convergence Acceleration for Parallel CFD Codes
     R.D. Williams, J. Hauser and R. Winkelmann,
    Proceedings of the Parallel CFD '96 conference, Capri, Italy
    July 1996. PDF

    1995

    "Infinite" Information on the Internet
    Caltech Engineering and Science magazine PDF

    A Newton-GMRES Method for the Parallel Navier-Stokes Equations
     J. Hauser, R.D. Williams, H.-G. Paap, M. Spel, J. Muylaert and R. Winkelmann
    Proceedings of the Parallel CFD '95 conference, Pasadena, California
    July 1995. PDF

    1994

    Parallel Computing Works!
    G. C. Fox, R. D. Williams and P. C. Messina,
    Morgan-Kaufmann, San Francisco, 1994 (available from Amazon)

    1993

    Unstructured hypersonic flow on a parallel machine

    These pictures show a parallel 3D adaptive unstructured mesh. The first two images show the pressure on the outside of a pipe of square cross section, that has a slot in it. Fluid moves from the top right to the bottom left; the main bow shock is reflected multiple times as the fluid moves down the pipe. The third image shows the surface of the unstructured tetrahedral mesh that was used for the computation; the mesh has self-adapted to the pressure gradient, meaning a finer mesh at the shocks. The fourth picture shows the decomposition of the mesh among 512 parallel processors: each colour represents a differentr processor. Adaptivity is evident here also, as each processor has an equal number of tetrahedral mesh cells.

    1992

    Strategies for Parallelizing a Navier-Stokes Code on the Intel Touchstone Machines
    J. Häuser and R. D. Williams,
    Int. J. Numerical Methods in Fluids, 15, 51 (1992)

    Voxel Databases: A Paradigm for Parallelism with Spatial Structure
     R. D. Williams,
    Concurrency, 4 (1992) 619. PDF

    1991

    Adaptive Parallel Meshes with Complex Geometry
     R. D. Williams
    in Numerical Grid Generation for Computational Fluid Dynamics, ed. A.-S. Arcilla et. al., Elsevier North-Holland, Amsterdam, 1991. PDF

    Performance of Dynamic Load Balancing Algorithms for Unstructured Mesh Calculations
     R. D. Williams,
    Concurrency, 3 (1991) 457. PDF

    Adaptive Parallel Meshes with Complex Geometry
    C. F. Baillie, R. D. Williams, S. M. Catterall and D. A. Johnston
    Nucl. Phys B348, 543 (1991)

    Performance of Dynamic Load Balancing Algorithms for Unstructured Mesh Calculations
    R. D. Williams,
    Concurrency, 3, 457 (1991) PDF users manual

    1990

    Benchmarking Advanced Architecture Computers
    P. Messina, C. F. Baillie, E. W. Felten, P. G. Hipes, D. W. Walker, R. D. Williams, et al,
    Concurrency, 2, 195 (1990)

    Crumpling Transition in Dynamically Triangulated Random Surfaces
    C. F. Baillie, R. D. Williams, D. A. Johnston
    Nuclear Physics B 335 (2): 469-501 (1990)

    Computational Aspects of Simulating Dynamically Triangulated Random Surfaces
    C. F. Baillie, R. D. Williams, D. A. Johnston
    Computer Physics Communications 58 (1-2): 105-117 (1990)

    1989

    Distributed Irregular Finite Elements
    R. D. Williams
    A software package for distributed parallel computing with unstructured triangular and tetrahedral meshes. PDF users manual

    Supersonic Flow in Parallel with an Unstructured Mesh
    R. D. Williams
    Concurrency, 1, 51 (1989) PDF.

    1988

    Free-Lagrange Hydrodynamics in Parallel
    R. D. Williams
    Parallel Computing 7, 439 (1988) PDF.

    1986

    Two Transitions in Tangentially Anchored Nematic Droplets
    R. D. Williams
    J. Phys. A19, 3211 (1986) PDF

    Critical Spin Dynamics of Europium Oxide
    S. W. Lovesey and R. D. Williams
    J. Phys. C19, L253 (1986)     PDF

    Scattering Response of a Phonon Damped Harmonic Oscillator
    R. D. Williams, S. W. Lovesey and W. Renz,
    Z. Physik B64, 129 (1986) PDF

    Neutron Scattering from a Substitutional Mass Defect
    R. D. Williams and S. W. Lovesey
    Z. Physik B62, 413 (1986) PDF

    1984

    Sub-Saturation Phases of Nuclear Matter
    R. D. Williams and S. E. Koonin,
    Nucl. Phys. A345, 844 (1984) PDF

    Bound-State Decay of Rhenium-187
    R. D. Williams, W. A. Fowler and S. E. Koonin,
    Astrophys. J. 281, 363 (1984) PDF

    1983

    Semiclassical Quantization in Many Dimensions
    R. D. Williams,
    Ph.D. Thesis, California Institute of Technology, 1983

    The Coupling of Phonons to a Helium Atom Adsorbed on Graphite
    R. D. Williams, M. W. Cole and S. E. Koonin,
    Phys. Rev. B28, 1076 (1983)

    Atomic Final-State Interactions in Tritium Decay
    R. D. Williams and S. E. Koonin,
    Phys. Rev. C27, 1815 (1983) PDF

    1982

    Semiclassical Quantization of the Shell Model
    R. D. Williams and S. E. Koonin,
    Nucl. Phys. A391, 79 (1982) PDF

    1981

    Direct Capture Cross Sections at Low Energy
    R. D. Williams and S. E. Koonin,
    Phys. Rev. C23, 2773 (1981) PDF