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Black Hole

Lensing of space time around a black hole. At Oxford we study black holes observationally and theoretically on all size and time scales - it is some of our core work.

Credit: ALAIN RIAZUELO, IAP/UPMC/CNRS. CLICK HERE TO VIEW MORE IMAGES.

Dr James Matthews

Royal Society University Research Fellow

Research theme

  • Astronomy and astrophysics
  • Particle astrophysics & cosmology

Sub department

  • Astrophysics

Research groups

  • Galaxy formation and evolution
  • MeerKAT
  • Pulsars, transients and relativistic astrophysics
  • Gamma-ray astronomy
james.matthews@physics.ox.ac.uk
Telephone: 01865(2)73299
Denys Wilkinson Building, room Undercroft
Website
  • About
  • Into the Cosmos
  • Publications

Evidence for a moderate spin from X-ray reflection of the high-mass supermassive black hole in the cluster-hosted quasar H1821+643

Monthly Notices of the Royal Astronomical Society Oxford University Press 514:2 (2022) 2568-2580

Authors:

Julia Sisk-Reynes, Christopher S Reynolds, James H Matthews, Robyn N Smith

Abstract:

We present an analysis of deep Chandra Low-Energy and High-Energy Transmission Grating archival observations of the extraordinarily luminous radio-quiet quasar H1821+643, hosted by a rich and massive cool-core cluster at redshift z = 0.3. These data sets provide high-resolution spectra of the AGN at two epochs, free from contamination by the intracluster medium and from the effects of photon pile-up, providing a sensitive probe of the iron-K band. At both epochs, the spectrum is well described by a power-law continuum plus X-ray reflection from both the inner accretion disc and cold, slowly moving distant matter. Adopting this framework, we proceed to examine the properties of the inner disc and the black hole spin. Using Markov chain Monte Carlo (MCMC) methods, we combine constraints from the two epochs assuming that the black hole spin, inner disc inclination, and inner disc iron abundance are invariant. The black hole spin is found to be modest, with a 90 per cent credible range of a ∗=0.62+0.22-0.37 and, with a mass MBH in the range log (MBH/M·) ∼9.2-10.5, this is the most massive black hole candidate for which a well-defined spin constraint has yet been obtained. The modest spin of this black hole supports previous suggestions that the most massive black holes may grow via incoherent or chaotic accretion and/or SMBH-SMBH mergers.
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A Decade of Black-Hole X-ray Binary Transients

Proceedings of Science 401 (2022)

Authors:

PA Charles, DAH Buckley, E Kotze, M Kotze, JK Thomas, P Gandhi, JA Paice, JP Lasota, JH Matthews, JF Steiner

Abstract:

The last decade has seen a significant gain in both space and ground-based monitoring capabilities, producing vastly better coverage of BH X-ray binaries during their (rare) transient events. This interval included two of the three brightest X-ray outbursts ever observed, namely V404 Cyg in 2015, and MAXI J1820+070 in 2018, as well as the outburst of Swift J1357.2-0933, the first such system to show variable period optical dipping. There are now superb multi-wavelength archives of these outbursts, both photometric and spectroscopic, that show substantial outflows in the form of jets and disc winds, and X-ray spectroscopy/timing that reveals how the inner accretion disc evolves. The ground-based AAVSO optical monitoring of the MAXI J1820+070 event was the most extensive ever obtained, revealing periodic variations that evolved as it approached its state transition. These modulations were of an amplitude never seen before, and suggested the development of an irradiation-driven disc warp that persisted through the transition. All these results have demonstrated the power of extensive multi-wavelength photometric and spectroscopic monitoring on all time-scales.

How Do Magnetic Field Models Affect Astrophysical Limits on Light Axion-like Particles? An X-Ray Case Study with NGC 1275

The Astrophysical Journal American Astronomical Society 930:1 (2022) 90

Authors:

James H Matthews, Christopher S Reynolds, MC David Marsh, Júlia Sisk-Reynés, Payton E Rodman
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The X-ray disc/wind degeneracy in AGN

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 513:1 (2022) 551-572

Authors:

ML Parker, GA Matzeu, JH Matthews, MJ Middleton, T Dauser, J Jiang, AM Joyce
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A persistent ultraviolet outflow from an accreting neutron star binary transient

Nature Springer Nature 603:7899 (2022) 52-57

Authors:

N Castro Segura, C Knigge, KS Long, D Altamirano, M Armas Padilla, C Bailyn, DAH Buckley, DJK Buisson, J Casares, P Charles, JA Combi, VA Cúneo, ND Degenaar, S del Palacio, M Díaz Trigo, R Fender, P Gandhi, M Georganti, C Gutiérrez, JV Hernandez Santisteban, F Jiménez-Ibarra, J Matthews, M Méndez, M Middleton, T Muñoz-Darias, M Özbey Arabacı, M Pahari, L Rhodes, TD Russell, S Scaringi, J van den Eijnden, G Vasilopoulos, FM Vincentelli, P Wiseman
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