A re--analysis of the iron line in the XMM-Newton data from the low/hard state in GX339--4 (2009)
Done, Chris, Trigo, Maria Diaz
The detection of an extremely broad iron line in XMM-Newton MOS data from the low/hard state of the black hole binary GX339-4 is the only piece of evidence which unambiguously conflicts with the...
Limits on spin determination from disc spectral fitting in GX 339-4 (2009)
Kolehmainen, Mari, Done, Chris
We attempt to constrain the black hole spin in GX339-4 from spectral fitting of disc dominated data using RXTE spectra from the three most recent outbursts. We use the best current models for the...
An additional soft X-ray component in the dim low/hard state of black hole binaries (2009)
Chiang, C. Y., Done, Chris, Still, M., Godet, O.
We test the truncated disc models using multiwavelength (optical/UV/X-ray) data from the 2005 hard state outburst of the black hole SWIFT J1753.5-0127. This system is both fairly bright and has...
We zoom in on the internal structure of the low-frequency quasi-periodic oscillation (LF QPO) often observed in black hole binary systems to investigate the physical nature of the lack of coherence...
We propose a physical framework for interpreting the broad band power spectra from black hole and neutron star binaries. We use the truncated disc/hot inner flow geometry, and assume that the hot...
The Ultraluminous State (2009)
Gladstone, J. C., Roberts, T. P., Done, Chris
(Abridged) We revisit the question of the nature of ULXs through a detailed investigation of their spectral shape, using the highest quality X-ray data available in the XMM-Newton public archives. We...
Low frequency QPO spectra and Lense-Thirring precession (2009)
Ingram, Adam, Done, Chris, Fragile, P Chris
We show that the low frequency QPO seen in the power density spectra of black hole binaries (and neutron stars) can be explained by Lense-Thirring precession. This has been proposed many times in the...
Reprocessing of X-rays in the outer accretion disc of the black hole binary XTE J1817--330 (2008)
Gierlinski, Marek, Done, Chris, Page, Kim
We build a simple model of the optical/UV emission from irradiation of the outer disc by the inner disc and coronal emission in black hole binaries. We apply this to the broadband Swift data from the...
RE J1034+396: The origin of the soft X-ray excess and QPO (2008)
Middleton, Matthew, Done, Chris, Ward, Martin, Gierlinski, Marek, Schurch, Nick
The X-ray quasi-periodic oscillation (QPO) seen in RE J1034+396 is so far unique amongst AGN. Here we look at the another unique feature of RE J1034+396, namely its huge soft X-ray excess, to see if...
A ~1-hour X-ray periodicity in an active galaxy RE J1034+396 (2008)
Gierlinski, Marek, Middleton, Matthew, Ward, Martin, Done, Chris
Active galactic nuclei and quasars are thought to be scaled up versions of Galactic black hole binaries, powered by accretion onto supermassive black holes with masses of 10^6-10^9 M_Sun, as opposed...
Gierlinski, Marek, Done, Chris, Page, Kim
The key aspect of the very successful truncated disc model for the low/hard X-ray spectral state in black hole binaries is that the geometrically thin disc recedes back from the last stable orbit at...
The accretion flow in the disk dominated state of black hole binaries has peak temperature and luminosity which vary together in such a way as to indicate an approximately constant emitting area. The...
Andrzej Zdziarski, W. Neil Johnson, Chris Done, David Smith, Kellie Mcnaron-brown
We have obtained the first average 2--500 keV spectra of Seyfert galaxies, using the data from Ginga and GRO OSSE. Our sample contains 3 classes of objects with markedly different spectra:...
Suzaku Results on Cygnus X-1 in the Low/Hard State (2008)
Makishima, Kazuo, Takahashi, Hiromitsu, Yamada, Shin'ya, Done, Chris, Kubota, Aya, Dotani, Tadayasu, ...
The black-hole binary Cygnus X-1 was observed for 17 ks with the Suzaku X-ray observatory in 2005 October, while it was in a low/hard state with a 0.7-300 keV luminosity of 4.6 x 10^37 erg/s. The XIS...
A Deep 0.3-10 keV Spectrum of the H$_{2}$O Maser Galaxy IC 2560 (2008)
Tilak, Avanti, Greenhill, Lincoln, Done, Chris, Madejski, Grzegorz
We present a new XMM-Newton spectrum of the Seyfert 2 nucleus of IC 2560, which hosts H$_{2}$O maser emission from an inclined Keplerian accretion disk. The X-ray spectrum shows soft excess due to...
Reeves, James, Done, Chris, Pounds, Ken, Terashima, Yuichi, Hayashida, Kiyoshi, Anabuki, Naohisa
We present a comparison between the 2001 XMM-Newton and 2005 Suzaku observations of the quasar, PG1211+143 at z=0.0809. Variability is observed in the 7 keV iron K-shell absorption line (at 7.6 keV...
High Energy spectra of Seyferts and Unification schemes (2007)
Middleton, Matthew, Done, Chris, Schurch, Nick
The Unified Model of AGN predicts the sole difference between Seyfert 1 and Seyfert 2 nuclei is the viewing angle with respect to an obscuring structure around the nucleus. High energy photons above...
Suzaku wide-band X-ray Spectroscopy of the Seyfert 2 AGN in NGC 4945 (2007)
Itoh, Takeshi, Done, Chris, Makishima, Kazuo, Madejski, Grzegorz, Awaki, Hisamitsu, Isobe, Naoki, ...
Suzaku observed a nearby Seyfert 2 galaxy NGC4945, which hosts one of the brightest active galactic nuclei above 20 keV. Combining data from the X-ray CCD camera (XIS) and the Hard X-ray Detector...
Modelling the behaviour of accretion flows in X-ray binaries (2007)
Done, Chris, Gierlinski, Marek, Kubota, Aya
(abridged) We review how the recent increase in X-ray and radio data from black hole and neutron star binaries can be merged together with theoretical advances to give a coherent picture of the...
The Origin of the soft excess in AGN (2007)
Done, Chris, Gierlinski, Marek, Sobolewska, Malgosia, Schurch, Nick
We discuss various ideas for the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised rather than where it is...
The origin of the soft excess in high L/L_Edd AGN (2007)
We discuss the origin of the soft X-ray excess seen in AGN. There are clear advantages to models where this arises from atomic processes in partially ionised material rather than where it is a true...
Can the soft excess in AGN originate from disc reflection? (2007)
Done, Chris, Nayakshin, Sergei
The soft excess seen in many AGN is most probably due to partially ionized material moving at relativistic speeds close to the black hole. There are currently two potential geometries for this...
Kubota, Aya, Dotani, Tadayasu, Cottam, Jean, Kotani, Taro, Done, Chris, Ueda, Yoshihiro, ...
We present the results of six Suzaku observations of the recurrent black hole transient 4U1630-472 during its decline from outburst from February 8 to March 23 in 2006. All observations show the...
What is the origin of the soft excess in AGN? (2006)
Sobolewska, Malgorzata A., Done, Chris
We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line...
Energy-dependent variability and the origin of the soft X-ray excess in AGN (2006)
Gierlinski, Marek, Done, Chris
The origin of the soft excess seen in many AGN below ~1 keV is still an unsolved problem. It is unlikely to represent a true continuum component as its characteristic 'temperature' shows a remarkable...
Analysing the atolls: X-ray spectral transitions of accreting neutron stars (2006)
Gladstone, Jeanette, Done, Chris, Gierlinski, Marek
We systematically analyze all the available X-ray spectra of disc accreting neutron stars (atolls and millisecond pulsars) from the RXTE database. We show that while these all have similar spectral...
Testing Accretion Disk Theory in Black Hole X-ray Binaries (2006)
Davis, Shane W., Done, Chris, Blaes, Omer M.
We present results from spectral modeling of three black hole X-ray binaries: LMC X-3, GRO J1655-40, and XTE J1550-564. Using a sample of disk dominated observations, we fit the data with a range of...
Black hole spin in GRS 1915+105 (2006)
Middleton, Matthew, Done, Chris, Gierlinski, Marek, Davis, Shane
Microquasars are galactic black hole binary systems with radio jets which can sometimes be spatially resolved to show superluminal motion. The first and best known of this class of objects is GRS...
The decline and fall of GRS 1915+105: the end is nigh? (2006)
The galactic microquasar GRS 1915+105 has been in a continuous state of outburst since 1992, over 20 times longer than any other black hole X-ray transient. Assuming that the outburst is powered via...
(truncated version) The X-ray spectra of Galactic binary systems in the very high state show both strong disk emission and a strong, steep tail to high energies. We use simultaneous optical-ASCA-RXTE...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
To be published in the proceedings of the 2005 ESLAB Symposium "Trends in Space Science and Cosmic Vision 2020", held at ESTEC, 19-21 April 2005, F. Favata (ed).
Truncated disc versus extremely broad iron line in XTE J1650-500 (2005)
Done, Chris, Gierlinski, Marek
There is growing evidence from both spectral and timing properties that there is a truncated inner accretion disc in low mass accretion rate Galactic black hole systems. The detection of extremely...
X-ray Emission from Megamaser Galaxy IC 2560 (2005)
Madejski, Greg, Done, Chris, Zycki, Piotr, Greenhill, Lincoln
Observation of the H2O megamaser galaxy IC 2560 with the Chandra Observatory reveals a complex spectrum composed of soft X-ray emission due to multi-temperature thermal plasma, and a hard continuum...
Accretion in Strong Gravity: From Galactic to Supermassive Black Holes (2005)
Done, Chris, Gierlinski, Marek
The galactic black hole binary systems give an observational template showing how the accretion flow changes as a function of increasing mass accretion rate, or L/L_Edd. These data can be synthetised...
Scaling variability from stellar to supermassive black holes (2005)
Done, Chris, Gierlinski, Marek
We investigate the correspondence between the variability seen in the stellar and supermassive black holes. Galactic Black Hole (GBH) power density spectra (PDS) are generally complex, and dependent...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly...
Trends in Space Astronomy and Cosmic Vision 2015-2025 (2005)
Turon, Catherine, Done, Chris, Quirrenbach, Andreas, Schneider, Peter, Aerts, Conny, Bazzano, Angela, ...
As a short introduction to the astronomy session, the response of the community to the Call for Themes issued by ESA and the specific themes selected by the Astronomy Working Group are briefly...
What is the origin of the soft excess in AGN? (2004)
Sobolewska, Malgorzata, Done, Chris
We investigate the nature of the soft excess below 1 keV observed in AGN. We use the XMM-Newton data of the low redshift, optically bright quasar, PG 1211+143, and we compare it with the Narrow Line...
Extreme Gravitational Lensing near Rotating Black Holes (2004)
We describe a new approach to calculating photon trajectories and gravitational lensing effects in the strong gravitational field of the Kerr black hole. These techniques are applied to explore both...
Observing braneworld black holes (2004)
Gregory, Ruth, Whisker, Richard, Beckwith, Kris, Done, Chris
Spacetime in the vicinity of an event horizon can be probed using observations which explore the dynamics of the accretion disc. Many high energy theories of gravity lead to modifications of the near...
Spectral transitions in X-ray Binaries (2004)
Done, Chris, Gierlinski, Marek
We systematically analyzed about a terabyte of data from Galactic binary systems to characterize how these spectra change as a function of mass accretion rate. With this volume of data we are able to...
Accurate Modelling of Relativistic Iron Lines from Accretion Discs (2004)
Observations of fluorescent iron lines from accreting black holes provide one of the best tests of strong field gravity available to date, and the only current observational tool to probe black hole...
Iron Line Profiles in Strong Gravity (2004)
We describe a new code which can accurately calculate the relativistic effects which distort the emission from an accretion disc around a black hole. We compare our results for a disk which extends...
The 1998 outburst of the bright Galactic black hole binary system XTE J1550-564 was used to constrain the accretion disc structure in the strongly Comptonised very high state spectra. These data show...
Mueller, Martin, Madejski, Greg, Done, Chris, Zycki, Piotr
For light curves sampled on an uneven grid of observation times, the shape of the power density spectrum (PDS) includes severe distortion effects due to the window function, and simulations of light...
Is the soft excess in AGN real? (2003)
Gierlinski, Marek, Done, Chris
We systematically analyse all publicly available XMM-Newton spectra of radio-quiet PG quasars. The soft X-ray excess in these objects is well modelled by an additional, cool, Compton scattering...
Black hole accretion discs: reality confronts theory (2003)
Gierlinski, Marek, Done, Chris
Disc spectra from highly luminous black hole binaries are observed to be rather simple, despite theoretical predictions to the contrary. We collate the disc-dominated spectra from multiple...
Simultaneous Chandra and RXTE observations of the nearby bright Seyfert 2 galaxy NGC4945 (2003)
Done, Chris, Madejski, Greg M., Zycki, Piotr T., Greenhill, Lincoln J.
We analyze recent simultaneous Chandra/RXTE observations of the Seyfert 2 galaxy NGC 4945. The unprecedented spatial resolution of Chandra means we are able to separate the spectra of the nucleus,...
The X-ray/gamma-ray spectrum of XTE J1550--564 in the very high state (2002)
Gierlinski, Marek, Done, Chris
We fit the broad-band X/gamma-ray spectrum (0.8-1000 keV) of the accreting black hole XTE J1550-564 in the very high state. The quasi-simultaneous data from ASCA, RXTE and OSSE show that the disc is...
Observing the effects of the event horizon in black holes (2002)
Done, Chris, Gierlinski, Marek
The key difference between neutron stars and black holes is the presence/absence of a solid surface. Recent attempts to detect this difference have concentrated on the quiescent luminosity, but here...
Kubota, Aya, Done, Chris, Makishima, Kazuo
The ultraluminous compact X-ray sources (ULXs) generally show a curving spectrum in the 0.7--10 keV ASCA bandpass, which looks like a high temperature analogue of the disk dominated high/soft state...
On the accretion geometry of Cyg X-1 in the low/hard state (2002)
Barrio, F. Eugenio, Done, Chris, Nayakshin, Sergei
We fit the broad-band RXTE PCA and HEXTE spectrum from 3--200 keV with reflection models which calculate the vertical ionization structure of an X-ray illuminated disc. We consider two geometries...
The X-ray spectrum of the atoll source 4U 1608-52 (2002)
Gierlinski, Marek, Done, Chris
The transient atoll source 4U 1608-52 had been extensively observed by the Rossi X-ray Timing Explorer RXTE during its 1998 outburst. We analyse its X-ray spectra as a function of inferred accretion...
Accretion Flows in X-ray Binaries (2002)
I review the X-ray observations of Galactic accreting black holes and neutron stars, and interpretions of these in terms of solutions of the accretion flow equations.
A comment on the colour-colour diagrams of Low Mass X-ray Binaries (2001)
Gierlinski, Marek, Done, Chris
Disc accreting neutron stars come in two distinct varieties, atolls and Z sources, named after their differently shaped tracks on a colour-colour diagram as the source luminosity changes. Here we...
Phase-resolved X-ray spectroscopy of the millisecond pulsar SAX J1808.4-3658 (2001)
Gierlinski, Marek, Done, Chris, Barret, Didier
We present new results based on RXTE observations of SAX J1808.4-3658. The X-ray spectrum can be fitted by a two-component model. We interpret the soft component as blackbody emission from a heated...
Accretion Flows in X--Ray Binaries and Active Galactic Nuclei (2001)
Hard X-ray emission is ubiquitous in accreting black holes, both in Galactic binary systems and in Active Galactic Nuclei. I review the different spectra which can be seen from these systems, and...
Phase-resolved spectra of the millisecond pulsar SAX J1808.4-3658 (2001)
Gierlinski, Marek, Done, Chris, Barret, Didier
We analyze the RXTE observations of the April 1998 outburst of SAX J1808.4-3658. We show that the soft blackbody component of the X-ray spectrum is from the hotspot on the neutron star surface, while...
We study the spectral properties of the first 14 observations of the rise to outburst phase of the X-ray transient J1550-564. Using the PCA and HEXTE instruments, we find that the 3-200 keV spectra...
Relativistic Distortions in the X-ray Spectrum of Cyg X-1 (1998)
We present the first significant detection of relativistic smearing of the X-ray reflection spectrum from the putative accretion disk in the low/hard state of Cyg X-1. The ionization state, and...
An unstable inner disk in Cyg X-1 ? (1998)
We present the first significant detection of relativistic smearing of the X-ray reflection spectrum from the putative accretion disk in the low/hard state of Cyg X--1. The ionization state, and...
Evolution of the accretion flow in Nova Muscae 1991 (1998)
Zycki, Piotr, Done, Chris, Smith, David
We identify the X-Ray reflected component in the Ginga spectra of Nova Muscae 1991, a Black Hole transient system used as the prototype for the recent model of Esin, McClintock & Narayan (1997) based...
Relativistically smeared X-ray reprocessed components in the GINGA spectra of GS 2023+338 (1997)
Zycki, Piotr, Done, Chris, Smith, David
We present results of spectral analysis of Ginga data obtained during the decline phase after the 1989 outburst of GS 2023+338 (V404 Cyg). Our analysis includes detailed modelling of the effects of...
Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE (1996)
Gierlinski, Marek, Zdziarski, Andrzej A., Done, Chris, Johnson, W. Neil, Ebisawa, Ken, Ueda, Yoshihiro, ...
We present four X-ray/gamma-ray spectra of Cyg X-1 observed in the hard ('low') state simultaneously by Ginga and GRO/OSSE on 1991 July 6. The 3-30 keV Ginga spectra are well represented by power...
The first simultaneous X-ray/gamma-ray observations of Cyg X-1 by Ginga and OSSE (1995)
Gierlinski, Marek, Zdziarski, Andrzej A., Johnson, W. Neil, Phlips, Bernard F., Ebisawa, Ken, Done, Chris
We present the results of 4 simultaneous observations of Cygnus X-1 by Ginga and OSSE. The X-ray/gamma-ray spectra can be described by an intrinsic continuum and a component due to Compton reflection...