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Reaching the peak of the quasar spectral energy distribution - I. Observations and models (2015)
Journal Article
Collinson, J., Ward, M., Done, C., Landt, H., Elvis, M., & McDowell, J. (2015). Reaching the peak of the quasar spectral energy distribution - I. Observations and models. Monthly Notices of the Royal Astronomical Society, 449(2), 2174-2193. https://doi.org/10.1093/mnras/stv362

We perform a spectral analysis of a sample of 11 medium redshift (1.5 ≲ z ≲ 2.2) quasars. Our sample all have optical spectra from the SDSS, infrared spectra from GNIRS and TripleSpec, and X-ray spectra from XMM–Newton. We first analyse the Balmer br... Read More about Reaching the peak of the quasar spectral energy distribution - I. Observations and models.

Complex narrow-line Seyfert 1s: high spin or high inclination? (2015)
Journal Article
Gardner, E., & Done, C. (2015). Complex narrow-line Seyfert 1s: high spin or high inclination?. Monthly Notices of the Royal Astronomical Society, 448(3), 2245-2259. https://doi.org/10.1093/mnras/stv168

Complex narrow-line Seyfert 1s (NLS1s), such as 1H 0707−495, differ from simple NLS1s like PG 1244+026 by showing stronger broad spectral features at Fe K and larger amplitude flux variability. These are correlated: the strongest Fe K features are se... Read More about Complex narrow-line Seyfert 1s: high spin or high inclination?.

The origin of ultrafast outflows in AGN: Monte Carlo simulations of the wind in PDS 456 (2014)
Journal Article
Hagino, K., Odaka, H., Done, C., Gandhi, P., Watanabe, S., Sako, M., & Takahashi, T. (2015). The origin of ultrafast outflows in AGN: Monte Carlo simulations of the wind in PDS 456. Monthly Notices of the Royal Astronomical Society, 446(1), 663-676. https://doi.org/10.1093/mnras/stu2095

Ultrafast outflows (UFOs) are seen in many AGN, giving a possible mode for AGN feedback on to the host galaxy. However, the mechanism(s) for the launch and acceleration of these outflows are currently unknown, with UV line driving apparently strongly... Read More about The origin of ultrafast outflows in AGN: Monte Carlo simulations of the wind in PDS 456.

Irradiated, colour-temperature-corrected accretion discs in ultraluminous X-ray sources (2014)
Journal Article
Sutton, A. D., Done, C., & Roberts, T. P. (2014). Irradiated, colour-temperature-corrected accretion discs in ultraluminous X-ray sources. Monthly Notices of the Royal Astronomical Society, 444(3), 2415-2427. https://doi.org/10.1093/mnras/stu1597

Although attempts have been made to constrain the stellar types of optical counterparts to ultraluminous X-ray sources (ULXs), the detection of optical variability instead suggests that they may be dominated by reprocessed emission from X-rays which... Read More about Irradiated, colour-temperature-corrected accretion discs in ultraluminous X-ray sources.

SUZAKU Observation of the Black Hole Binary 4U 1630-47 in the Very High State (2014)
Journal Article
Hori, T., Ueda, Y., Shidatsu, M., Kawamuro, T., Kubota, A., Done, C., …Nagayama, T. (2014). SUZAKU Observation of the Black Hole Binary 4U 1630-47 in the Very High State. Astrophysical Journal, 790(1), Article 20. https://doi.org/10.1088/0004-637x/790/1/20

We report the results from an X-ray and near-infrared observation of the Galactic black hole binary 4U 1630-47 in the very high state (VHS), performed with Suzaku and the Infrared Survey Facility around the peak of the 2012 September-October outburst... Read More about SUZAKU Observation of the Black Hole Binary 4U 1630-47 in the Very High State.

Spectral and Timing Properties of the Black Hole X-Ray Binary H1743-322 in the Low/Hard State Studied with Suzaku (2014)
Journal Article
Shidatsu, M., Ueda, Y., Yamada, S., Done, C., Hori, T., Yamaoka, K., …Moritani, Y. (2014). Spectral and Timing Properties of the Black Hole X-Ray Binary H1743-322 in the Low/Hard State Studied with Suzaku. Astrophysical Journal, 789(2), Article 100. https://doi.org/10.1088/0004-637x/789/2/100

We report on the results from Suzaku observations of the Galactic black hole X-ray binary H1743–322 in the low/hard state during its outburst in 2012 October. We appropriately take into account the effects of dust scattering to accurately analyze the... Read More about Spectral and Timing Properties of the Black Hole X-Ray Binary H1743-322 in the Low/Hard State Studied with Suzaku.

A physical model for the X-ray time lags of narrow-line Seyfert type 1 active galactic nuclei (2014)
Journal Article
Gardner, E., & Done, C. (2014). A physical model for the X-ray time lags of narrow-line Seyfert type 1 active galactic nuclei. Monthly Notices of the Royal Astronomical Society, 442(3), 2456-2473. https://doi.org/10.1093/mnras/stu1026

We study the origin of the soft X-ray excess seen in the ‘simple’ narrow-line Seyfert 1 galaxy PG1244+026 using all available spectral-timing information. This object shows the now ubiquitous switch between soft leading the hard band on long time-sca... Read More about A physical model for the X-ray time lags of narrow-line Seyfert type 1 active galactic nuclei.

A compact, metal-rich, kpc-scale outflow in FBQS J0209-0438: detailed diagnostics from HST/COS extreme UV observations (2014)
Journal Article
Finn, C. W., Morris, S. L., Crighton, N. H., Hamann, F., Done, C., Theuns, T., …Worseck, G. (2014). A compact, metal-rich, kpc-scale outflow in FBQS J0209-0438: detailed diagnostics from HST/COS extreme UV observations. Monthly Notices of the Royal Astronomical Society, 440(4), 3317-3340. https://doi.org/10.1093/mnras/stu518

We present HST/COS observations of highly ionized absorption lines associated with a radio-loud quasar (QSO) at z = 1.1319. The absorption system has multiple velocity components, with an overall width of ≈600 km s−1, tracing gas that is largely outf... Read More about A compact, metal-rich, kpc-scale outflow in FBQS J0209-0438: detailed diagnostics from HST/COS extreme UV observations.

X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026 (2014)
Journal Article
Alston, W., Done, C., & Vaughan, S. (2014). X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026. Monthly Notices of the Royal Astronomical Society, 439(2), 1548-1555. https://doi.org/10.1093/mnras/stu005

We analyse the X-ray time-lags in the narrow line Seyfert 1 (NLS1) galaxy PG 1244+026 (MBH ∼ 107 M⊙, L/LEdd ∼ 1). The time delay between the soft (0.3–0.7 keV) and harder (1.2–4.0 keV) variations shows the well-established switch from hard lags at lo... Read More about X-ray time delays in the narrow line Seyfert 1 galaxy PG 1244+026.

An imperfect double: probing the physical origin of the low-frequency quasi-periodic oscillation and its harmonic in black hole binaries (2013)
Journal Article
Axelsson, M., Done, C., & Hjalmarsdotter, L. (2014). An imperfect double: probing the physical origin of the low-frequency quasi-periodic oscillation and its harmonic in black hole binaries. Monthly Notices of the Royal Astronomical Society, 438(1), 657-662. https://doi.org/10.1093/mnras/stt2236

We extract the spectra of the strong low-frequency quasi-periodic oscillation (QPO) and its harmonic during the rising phase of an outburst in the black hole binary XTE J1550-564. We compare these frequency-resolved spectra to the time-averaged spect... Read More about An imperfect double: probing the physical origin of the low-frequency quasi-periodic oscillation and its harmonic in black hole binaries.

The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average (2013)
Journal Article
Starling, R., Done, C., Jin, C., Romero-Colmenero, E., Potter, S., Wiersema, K., …Lobban, A. (2014). The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average. Monthly Notices of the Royal Astronomical Society, 437(4), 3929-3938. https://doi.org/10.1093/mnras/stt2201

RE J2248−511 is one of only 14 non-blazar active galactic nuclei (AGN) detected in the far-ultraviolet (FUV) by the ROSAT Wide Field Camera implying a large ultrasoft X-ray flux. This soft X-ray excess is strongly variable on year time-scales, a comm... Read More about The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average.

What powers the most relativistic jets? – I. BL Lacs (2013)
Journal Article
Gardner, E., & Done, C. (2014). What powers the most relativistic jets? – I. BL Lacs. Monthly Notices of the Royal Astronomical Society, 438(1), 779-788. https://doi.org/10.1093/mnras/stt2246

The dramatic relativistic jets pointing directly at us in BL Lacertae (BL Lac) objects can be well modelled by bulk motion beaming of synchrotron self-Compton emission powered by a low Eddington fraction accretion flow. Nearly 500 of these active gal... Read More about What powers the most relativistic jets? – I. BL Lacs.

The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries (2013)
Journal Article
Kolehmainen, M., Done, C., & Díaz Trigo, M. (2014). The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries. Monthly Notices of the Royal Astronomical Society, 437(1), 316-326. https://doi.org/10.1093/mnras/stt1886

The inner radius of the accretion disc around a black hole in the low/hard state can be measured in one of two ways. First, via the extent of broadening of the iron emission line, and secondly, from the luminosity and temperature of the weak soft com... Read More about The soft component and the iron line as signatures of the disc inner radius in Galactic black hole binaries.

Jets and the accretion flow in low-luminosity black holes (2013)
Journal Article
Gardner, E., & Done, C. (2013). Jets and the accretion flow in low-luminosity black holes. Monthly Notices of the Royal Astronomical Society, 434(4), 3454-3462. https://doi.org/10.1093/mnras/stt1257

The X-ray spectra of black hole binaries (BHB) in the low/hard state (LHS) first harden as the flux decreases, then soften. This change in behaviour has been variously attributed to either the X-rays switching from being produced in the flow to being... Read More about Jets and the accretion flow in low-luminosity black holes.

A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies (2013)
Journal Article
Done, C., Jin, C., Middleton, M., & Ward, M. (2013). A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies. Monthly Notices of the Royal Astronomical Society, 434(3), 1955-1963. https://doi.org/10.1093/mnras/stt1138

We show that disc continuum fitting can be used to constrain black hole spin in a subclass of narrow-line Seyfert 1 (NLS1) active galactic nuclei as their low mass and high mass accretion rate means that the disc peaks at energies just below the soft... Read More about A new way to measure supermassive black hole spin in accretion disc-dominated Active Galaxies.

Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku (2013)
Journal Article
Yamada, S., Torii, S., Mineshige, S., Ueda, Y., Kubota, A., Gandhi, P., …Makishima, K. (2013). Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku. Astrophysical Journal Letters, 767(2), Article L35. https://doi.org/10.1088/2041-8205/767/2/l35

We present observations of a transient He-like Fe Kα absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the... Read More about Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku.