Dr James Matthews

Astrophysicist

About Me

I’m an astrophysicist working at the University of Cambridge. My research involves understanding two main topics: the origins of ultra-high energy cosmic rays and the physics of winds and jets from accreting systems. These two subjects are inextricably linked.

You can find more details on my research, outreach and publications below, read my PhD thesis or read my CV.

Some recent highlights and links to data or movies:

  • Recent paper on stratified disc wind models for the AGN broad-line region and accompanying data and notebooks.
  • Information and movies from a recent paper about UHECRs from shocks in the lobes of radio galaxies.
  • Data from the Matthews et al. 2016 simulation grid.
  • A recent press releases regarding the wind in J1357.2: Royal Astrononomical Society, CNN or the University of Southampton.
  • Contact

    matthews [at] ast [dot] cam [dot] ac [dot] uk

    Institute of Astronomy
    University of Cambridge, Madingley Road, Cambridge, CB3 0HA

    Github icon Github
    ORCID iD icon ORCID

    Projects

    Cosmic Ray Acceleration

    It is not yet understood where the highest energy cosmic rays originate. One of my main research goals is to figure out whether jets from AGN can accelerate the highest energy cosmic rays. More info here.

    MHD turbulence and plasma

    Turbulence is a crucial aspect of cosmic ray acceleration, as it allows scattering of the particles across a shock front. It turns out that cosmic rays can self-generate this turbulence via streaming instabilities, physics that is also important in feedback processes in clusters.

    Disc Winds in Accreting Systems

    Outflows are ubiquitous in accreting systems. I spent my PhD developing a Monte Carlo radiative transfer and photoionization code, and used it to synthesize spectra of accreting objects with associated outflows.

    Quasar and AGN unification and orientation

    It would be rather elegant if all accreting supermassive black holes could essentially be described by their mass, Eddington ratio and viewing angle. While countless other complications doubtless exist, I am very interested in testing this paradigm. Image credit: Shen & Ho 2014.

    Public Engagement

    My public engagement work has involved taking this huge inflatable planetarium into local schools, but also activities with the homeless in Oxford. I also enjoy giving public talks. These are often about alien life as that is the most popular topic for school children, but I've also given more specialised talks on winds and tori around black holes.

    Selected Publications

    Here are some of my favourite papers. You can find a full list of publications on ADS.

    Stratified disc wind models for the AGN broad-line region: ultraviolet, optical and X-ray properties 2019
    Matthews, J. H., Knigge, C., Higginbottom, N., Long, K. S., et al.,
    MNRAS in press.

    Hot, dense He II outflows during the 2017 outburst of the X-ray transient Swift J1357.2-0933 2019
    Charles, P., Matthews, J. H., Buckley, D., Gandhi P.; Kotze, E.; Paice, J.
    MNRAS Letters in press.

    Cosmic ray acceleration by shocks: spectral steepening due to turbulent magnetic field amplification 2019
    Bell, A., Matthews, J. H., Blundell, K.
    MNRAS, 488, 2466.

    Ultra-high energy cosmic rays from shocks in the lobes of radio galaxies 2019
    Matthews, J. H., Bell, A., Blundell, K., Araudo, A.,
    MNRAS, 482, 4303, arXiv:1810.12350

    The origin of radio emission in broad absorption line quasars: Results from the LOFAR Two-metre Sky Survey 2018
    Morabito, L., K., Matthews, J. H., P.N. Best, G. Gurkan, M. Jarvis, et al.
    A&A, in press

    Fornax A, Centaurus A other radio galaxies as sources of ultra-high energy cosmic rays 2018
    Matthews, J. H., Bell. A., Blundell, K., Araudo, A.,
    MNRAS Letters, 479, 76

    Radiation-hydrodynamic simulations of thermally driven disc winds in X-ray binaries 2017
    Higginbottom, N., Knigge, C., Long, K. S. Matthews, J. H., et al.,
    MNRAS, 479, 3651

    Cosmic Ray Acceleration by Relativistic Shocks: Limits and Estimates 2018
    Bell. A., Araudo, A., Matthews, J. H., Blundell, K.
    MNRAS, 473, 2364

    Amplification of perpendicular and parallel magnetic fields by cosmic ray currents 2017
    Matthews, J. H., Bell. A., Blundell, K., Araudo, A.
    MNRAS, 469, 1849

    Quasar emission lines as probes of orientation: implications for disc wind geometries and unification 2017
    Matthews, J. H.; Knigge, C.; Long, K. S.
    MNRAS, 467, 2571

    The reverberation signatures of rotating disc winds in active galactic nuclei 2017
    Mangham, S. W., Knigge, C., Matthews, J. H.; Long, K. S.; Sim, S. A.; Higginbottom, N.,
    MNRAS, in press, DOI:10.1093/mnras/stx1863

    Testing Quasar Unification: Radiative Transfer in Clumpy Winds 2016
    Matthews, J. H.; Knigge, C.; Long, K. S.; Sim, S. A.; Higginbottom, N.. Mangham, S. W.
    MNRAS, 458, 293

    The impact of accretion disc winds on the optical spectra of cataclysmic variables 2015
    Matthews, J. H.; Knigge, C.; Long, K. S.; Sim, S. A.; Higginbottom, N.
    MNRAS, 450, 3.

    Line-driven Disk Winds in Active Galactic Nuclei: The Critical Importance of Ionization and Radiative Transfer 2014
    Higginbottom, N.; Proga, D.; Knigge, C.; Long, K. S.; Matthews, J. H.; Sim, S. A.
    The Astrophysical Journal, 789, 1.

    Talk Highlights

    Invited Talk: Particle Acceleration in Jets July 2019
    A Centenary of Jets, Jodrell Bank

    Invited Review: Disc Winds in Accreting White Dwarfs July 2019
    From Winds to Jets, Amsterdam

    Invited Talk: UHECRs from Radio Galaxies December 2018
    Hillas Symposium, Heidelberg

    Invited Talk: UHECRs from Radio Galaxies November 2018
    Particle Acceleration Conference, Calabria

    Contributed Talk: UHECRs from Radio Galaxies November 2018
    UHECR 2018, Paris

    Invited Colloquia: UHECRs from Radio Galaxies 2017-2018
    Belfast, Manchester, Nottingham, Oxford, Southampton

    Testing Quasar Unification with Radiative Transfer Simulations June 2017
    AGN Winds on the Georgia Coast, Jekyll Island, GA

    Invited Review: Ultraviolet Astronomy March 2017
    Broadband Astrophysical Processes, Southampton

    Disc Winds Matter! Their impact on the optical spectra of cataclysmic variables September 2015
    The Golden Age of Cataclysmic Variables, Palermo, Italy

    Modelling the Spectra of Quasars: Clumpy Winds and X-ray Properties June 2015
    The Extremes of Black Hole Accretion, Madrid, Spain

    Modelling the Spectra of Quasars: Clumpy Winds and X-ray Properties June 2015
    Black Hole Accretion and AGN Feedback, Shanghai, China

    Public Talk- The Search For Alien Life 2015
    Stargazing Live on campus event, University of Southampton

    Modelling the Spectra of Quasars June 2014
    Accretion Disc Winds Meeting, Durham, UK

    The Impact of Disc winds on the optical spectra of Cataclysmic Variables 2012
    Cataclysmic Variables Meeting, Columbia University, New York

    Searching for Nearby Planets During Predicted Mesolensing Events 2012
    Exoplanet Lunch, Harvard CfA, USA