61 citations · 184 across the 6 of their papers we have counts for
6 papers
Origins of the UV/X-ray Relation in Arakelian 120
Ra'ad David Mahmoud, Chris Done, Delphine Porquet +1
We explore the accretion geometry in Arakelian 120 using intensive UV and X-ray monitoring from \textit{Swift}. The hard X-rays ( keV) show large amplitude, fast (few-day) va…
Looking for the underlying cause of black hole X-ray variability in GRMHD simulations
D. A. Bollimpalli, R. Mahmoud, C. Done +4
Long-term observations have shown that black hole X-ray binaries exhibit strong, aperiodic variability on time-scales of a few milliseconds to seconds. The observed light curves di…
Discarding the disc in a changing state AGN: the UV/X-ray relation in NGC 4151
Ra'ad D. Mahmoud, Chris Done
Recent monitoring campaigns designed to map the accretion regime in AGN show major discrepancies with models where the optical/ultraviolet (UV) is produced by X-ray-illuminated, op…
Reverberation Reveals the Truncated Disc in the Hard State of GX 339-4
Ra'ad D. Mahmoud, Chris Done, Barbara De Marco
The nature and geometry of the hard state in black hole binaries is controversial. The broadband continuum spectrum and fast variability properties can be explained in a model wher…
A Physical Model for the Spectral-Timing Properties of Accreting Black Holes
Ra'ad D. Mahmoud, Chris Done
We develop new techniques to deconvolve the radial structure of the X-ray emission region in the bright low/hard state of the black hole Cygnus X-1 using both spectral and timing d…
Modelling the Energy Dependence of Black Hole Binary Flows
Ra'ad D. Mahmoud, Chris Done
We build a full spectral-timing model for the low/hard state of black hole binaries assuming that the spectrum of the X-ray hot flow can be produced by two Comptonisation zones. Sl…