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Fast variability as a probe of the smallest regions around accreting black holes (2013)
Journal Article
Axelsson, M., Hjalmarsdotter, L., & Done, C. (2013). Fast variability as a probe of the smallest regions around accreting black holes. Monthly Notices of the Royal Astronomical Society, 431(2), 1987-1994. https://doi.org/10.1093/mnras/stt315

We extract the spectra of the fastest variability (above 10 Hz) from the black hole XTE J1550−564 during a transition from hard to soft state on the rise to outburst. We confirm previous results that the rapid variability contains no significant disc... Read More about Fast variability as a probe of the smallest regions around accreting black holes.

Bright radio emission from an ultraluminous stellar-mass microquasar in M 31 (2013)
Journal Article
Middleton, M. J., Miller-Jones, J. C., Markoff, S., Fender, R., Henze, M., Hurley-Walker, N., …Grainge, K. (2013). Bright radio emission from an ultraluminous stellar-mass microquasar in M 31. Nature, 493(7431), 187-190. https://doi.org/10.1038/nature11697

A subset of ultraluminous X-ray sources (those with luminosities of less than 1040 erg s−1; ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of ~5–20 , probably by means of an accretion disk2, 3. The X-ray and ra... Read More about Bright radio emission from an ultraluminous stellar-mass microquasar in M 31.

The effect of frame dragging on the iron Kα line in X-ray binaries (2012)
Journal Article
Ingram, A., & Done, C. (2012). The effect of frame dragging on the iron Kα line in X-ray binaries. Monthly Notices of the Royal Astronomical Society, 427(2), 934-947. https://doi.org/10.1111/j.1365-2966.2012.21907.x

The clear characteristic time-scale picked out by the low-frequency quasi-periodic oscillations (QPOs) seen in many black hole and neutron star binaries has the potential to provide a very powerful diagnostic of the inner regions of the accretion flo... Read More about The effect of frame dragging on the iron Kα line in X-ray binaries.

A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties (2012)
Journal Article
Jin, C., Ward, M., & Done, C. (2012). A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties. Monthly Notices of the Royal Astronomical Society, 425(2), 907-929. https://doi.org/10.1111/j.1365-2966.2012.21272.x

In this third paper in a series of three, we present a detailed study of the broad-band spectral energy distribution (SED) of active galactic nuclei (AGNs) based on a nearby unobscured type 1 AGN sample. We perform a systematic cross-correlation stud... Read More about A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties.

A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra (2012)
Journal Article
Jin, C., Ward, M., & Done, C. (2012). A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra. Monthly Notices of the Royal Astronomical Society, 422(4), 3268-3284. https://doi.org/10.1111/j.1365-2966.2012.20847.x

In this second paper in a series of three, we study the properties of the various emission features and underlying continuum in the optical spectra of type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. W... Read More about A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra.

The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source (2012)
Journal Article
Middleton, M., Sutton, A., Roberts, T., Jackson, F., & Done, C. (2012). The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source. Monthly Notices of the Royal Astronomical Society, 420(4), 2969-2977. https://doi.org/10.1111/j.1365-2966.2011.20145.x

A new, transient ultraluminous X-ray source (ULX) was recently discovered by Chandra in M31 with a luminosity at ∼5 × 1039 erg s−1. Here we analyse a series of five subsequent XMM–Newton observations. These show a steady decline in X-ray luminosity o... Read More about The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source.

Intrinsic disc emission and the soft X-ray excess in active galactic nuclei (2012)
Journal Article
Done, C., Davis, S., Jin, C., Blaes, O., & Ward, M. (2012). Intrinsic disc emission and the soft X-ray excess in active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 420(3), 1848-1860. https://doi.org/10.1111/j.1365-2966.2011.19779.x

Narrow-line Seyfert 1 (NLS1) galaxies have low-mass black holes and mass accretion rates close to (or exceeding) Eddington, so a standard blackbody accretion disc should peak in the extreme ultraviolet. However, the lack of true absorption opacity in... Read More about Intrinsic disc emission and the soft X-ray excess in active galactic nuclei.

A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling (2012)
Journal Article
Jin, C., Ward, M., Done, C., & Gelbord, J. (2012). A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling. Monthly Notices of the Royal Astronomical Society, 420(3), 1825-1847. https://doi.org/10.1111/j.1365-2966.2011.19805.x

We present modelling and interpretation of the continuum and emission lines for a sample of 51 unobscured type 1 active galactic nuclei (AGNs). All of these AGNs have high-quality spectra from both XMM–Newton and the Sloan Digital Sky Survey. We exte... Read More about A combined optical and X-ray study of unobscured type 1 active galactic nuclei - I. Optical spectra and spectral energy distribution modelling.

The evolution of active galactic nuclei across cosmic time : what is downsizing? (2012)
Journal Article
Fanidakis, N., Baugh, C., Benson, A., Bower, R., Cole, S., Done, C., …del P. Lagos, C. (2012). The evolution of active galactic nuclei across cosmic time : what is downsizing?. Monthly Notices of the Royal Astronomical Society, 419(4), 2797-2820. https://doi.org/10.1111/j.1365-2966.2011.19931.x

We use a coupled model of the formation and evolution of galaxies and black holes (BHs) to study the evolution of active galactic nuclei (AGNs) in a cold dark matter universe. The model is embedded in the galaxy formation code GALFORM and predicts th... Read More about The evolution of active galactic nuclei across cosmic time : what is downsizing?.

Modelling variability in black hole binaries: linking simulations to observations (2012)
Journal Article
Ingram, A., & Done, C. (2012). Modelling variability in black hole binaries: linking simulations to observations. Monthly Notices of the Royal Astronomical Society, 419(3), 2369-2378. https://doi.org/10.1111/j.1365-2966.2011.19885.x

Black hole accretion flows show rapid X-ray variability. The power spectral density (PSD) of this is typically fit by a phenomenological model of multiple Lorentzians for both the broad-band noise and quasi-periodic oscillations (QPOs). Our previous... Read More about Modelling variability in black hole binaries: linking simulations to observations.