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Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy (2016)
Journal Article
Collinson, J., Ward, M., Landt, H., Done, C., Elvis, M., & McDowell, J. (2017). Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy. Monthly Notices of the Royal Astronomical Society, 465(1), 358-382. https://doi.org/10.1093/mnras/stw2666

We continue our study of the spectral energy distributions (SEDs) of 11 active galactic nuclei (AGN) at 1.5 < z < 2.2, with optical–near-infrared (NIR) spectra, X-ray data and mid-IR photometry. In a previous paper, we presented the observations and... Read More about Reaching the peak of the quasar spectral energy distribution – II. Exploring the accretion disc, dusty torus and host galaxy.

On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342 (2016)
Journal Article
Landt, H., Ward, M., Baloković, M., Kynoch, D., Storchi-Bergmann, T., Boisson, C., …Stern, D. (2017). On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342. Monthly Notices of the Royal Astronomical Society, 464(3), 2565-2576. https://doi.org/10.1093/mnras/stw2447

Narrow-line Seyfert 1 galaxies have been identified by the Fermi Gamma-Ray Space Telescope as a rare class of γ-ray emitting active galactic nuclei. The lowest redshift candidate among them is the source 1H 0323+342. Here we present quasi-simultaneou... Read More about On the black hole mass of the γ-ray emitting narrow-line Seyfert 1 galaxy 1H 0323+342.

Testing the completeness of the SDSS colour selection for ultramassive, slowly spinning black holes (2016)
Journal Article
Bertemes, C., Trakhtenbrot, B., Schawinski, K., Done, C., & Elvis, M. (2016). Testing the completeness of the SDSS colour selection for ultramassive, slowly spinning black holes. Monthly Notices of the Royal Astronomical Society, 463(4), 4041-4051. https://doi.org/10.1093/mnras/stw2207

We investigate the sensitivity of the colour-based quasar selection algorithm of the Sloan Digital Sky Survey (SDSS) to several key physical parameters of supermassive black holes (SMBHs), focusing on BH spin (a*) at the high BH-mass regime (MBH ≥ 10... Read More about Testing the completeness of the SDSS colour selection for ultramassive, slowly spinning black holes.

A disc wind interpretation of the strong Fe K$\alpha$ features in 1H 0707-495 (2016)
Journal Article
Hagino, K., Odaka, H., Done, C., Tomaru, R., Watanabe, S., & Takahashi, T. (2016). A disc wind interpretation of the strong Fe K$\alpha$ features in 1H 0707-495. Monthly Notices of the Royal Astronomical Society, 461(1), 3954-3963. https://doi.org/10.1093/mnras/stw1579

1H 0707−495 is the most convincing example of a supermassive black hole with an X-ray spectrum being dominated by extremely smeared, relativistic reflection, with the additional requirement of strongly supersolar iron abundance. However, here we show... Read More about A disc wind interpretation of the strong Fe K$\alpha$ features in 1H 0707-495.

An optically thick disk wind in GRO J1655-40? (2016)
Journal Article
Shidatsu, M., Done, C., & Ueda, Y. (2016). An optically thick disk wind in GRO J1655-40?. Astrophysical Journal, 823(2), Article 159. https://doi.org/10.3847/0004-637x/823/2/159

We revisited the unusual wind in GRO J1655−40, detected with Chandra in 2005 April, using long-term Rossi X-ray Timing Explorer X-ray data and simultaneous optical/near-infrared photometric data. This wind is the most convincing case for magnetic dri... Read More about An optically thick disk wind in GRO J1655-40?.

The X-ray spectral evolution of the ultraluminous X-ray source Holmberg IX X-1 (2016)
Journal Article
Luangtip, W., Roberts, T., & Done, C. (2016). The X-ray spectral evolution of the ultraluminous X-ray source Holmberg IX X-1. Monthly Notices of the Royal Astronomical Society, 460(4), 4417-4432. https://doi.org/10.1093/mnras/stw1282

We present a new analysis of X-ray spectra of the archetypal ultraluminous X-ray source (ULX) Holmberg IX X-1 obtained by the Swift, XMM–Newton and NuSTAR observatories. This ULX is a persistent source, with a typical luminosity of ∼1040 erg s−1, tha... Read More about The X-ray spectral evolution of the ultraluminous X-ray source Holmberg IX X-1.

A quasi-periodic modulation of the iron line centroid energy in the black hole binary H1743-322 (2016)
Journal Article
Ingram, A., van der Klis, M., Middleton, M., Done, C., Altamirano, D., Heil, L., …Axelsson, M. (2016). A quasi-periodic modulation of the iron line centroid energy in the black hole binary H1743-322. Monthly Notices of the Royal Astronomical Society, 461(2), 1967-1980. https://doi.org/10.1093/mnras/stw1245

Accreting stellar-mass black holes often show a ‘Type-C’ quasi-periodic oscillation (QPO) in their X-ray flux and an iron emission line in their X-ray spectrum. The iron line is generated through continuum photons reflecting off the accretion disc, a... Read More about A quasi-periodic modulation of the iron line centroid energy in the black hole binary H1743-322.

The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and its implications for the trigger for relativistic jets (2016)
Journal Article
Done, C., & Jin, C. (2016). The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and its implications for the trigger for relativistic jets. Monthly Notices of the Royal Astronomical Society, 460(2), 1716-1724. https://doi.org/10.1093/mnras/stw1070

Relativistic reflection models of the X-ray spectrum of the ‘complex’ Narrow Line Seyfert 1 (NLS1) 1H 0707−495 require a high-spin, moderate-inclination, low-mass black hole. With these parameters fixed, the observed optical/UV emission directly dete... Read More about The mass and spin of the extreme Narrow Line Seyfert 1 Galaxy 1H 0707-495 and its implications for the trigger for relativistic jets.

Tracking the energetics of the non-thermal disc–corona–jet in the very high state GX 339 − 4 (2016)
Journal Article
Kubota, A., & Done, C. (2016). Tracking the energetics of the non-thermal disc–corona–jet in the very high state GX 339 − 4. Monthly Notices of the Royal Astronomical Society, 458(4), 4238-4249. https://doi.org/10.1093/mnras/stw585

The dramatic hard–soft spectral transition in black hole binaries is important as it is associated with the collapse of the jet and with the strongest low-frequency quasi-periodic oscillations (QPOs). These transition spectra (intermediate and very h... Read More about Tracking the energetics of the non-thermal disc–corona–jet in the very high state GX 339 − 4.

Revealing the nature of the QPO and its harmonic in GX 339-4 using frequency-resolved spectroscopy (2016)
Journal Article
Axelsson, M., & Done, C. (2016). Revealing the nature of the QPO and its harmonic in GX 339-4 using frequency-resolved spectroscopy. Monthly Notices of the Royal Astronomical Society, 458(2), 1778-1784. https://doi.org/10.1093/mnras/stw464

We use frequency-resolved spectroscopy to examine the energy spectra of the prominent low-frequency quasi-periodic oscillation (QPO) and its harmonic in GX 339-4. We track the evolution of these spectra as the source makes a transition from a bright... Read More about Revealing the nature of the QPO and its harmonic in GX 339-4 using frequency-resolved spectroscopy.

Limits on pair production and multizone Comptonization: the broad-band X/γ-ray spectrum of XTE J1550–564 revisited (2016)
Journal Article
Hjalmarsdotter, L., Axelsson, M., & Done, C. (2016). Limits on pair production and multizone Comptonization: the broad-band X/γ-ray spectrum of XTE J1550–564 revisited. Monthly Notices of the Royal Astronomical Society, 456(4), 4354-4363. https://doi.org/10.1093/mnras/stv2909

At high luminosities black hole binaries show spectra with a strong disc component accompanied by an equally strong tail where at least some of the electrons are non-thermal. We reanalyse the simultaneous ASCA–RXTE–OSSE data from the 1998 outburst of... Read More about Limits on pair production and multizone Comptonization: the broad-band X/γ-ray spectrum of XTE J1550–564 revisited.

A variable ULX and possible IMBH candidate in M51a (2016)
Journal Article
Earnshaw, H. M., Roberts, T. P., Heil, L. M., Mezcua, M., Walton, D. J., Done, C., …Sutton, A. D. (2016). A variable ULX and possible IMBH candidate in M51a. Monthly Notices of the Royal Astronomical Society, 456(4), 3840-3854. https://doi.org/10.1093/mnras/stv2945

Ultraluminous X-ray source (ULX)-7, in the northern spiral arm of M51, demonstrates unusual behaviour for an ULX, with a hard X-ray spectrum but very high short-term variability. This suggests that it is not in a typical ultraluminous state. We analy... Read More about A variable ULX and possible IMBH candidate in M51a.