Search Publications
The magnetic field in the X-ray corona of Cygnus X-1
Malzac, J.; Bouchet, L.; De Cesare, G. +2 more
The different electron distributions in the hard and soft spectral states of black hole binaries could be caused by kinetic processes and changing because of varying physical conditions in the corona. In the presence of a magnetic field in the corona, the electron distribution can appear thermal, even when acceleration mechanisms would produce non…
The closest black holes
Maccarone, T. J.; Heywood, I.; Fender, R. P.
Starting from the assumption that there is a large population (≥108) of stellar-mass isolated black holes (IBH) distributed throughout our Galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that may be associated with such a population. We simulate the nearby (radius 250 pc) part of this popula…
The shocked outflow in NGC 4051 - momentum-driven feedback, ultrafast outflows and warm absorbers
King, A. R.; Pounds, K. A.
An extended XMM-Newton observation of the Seyfert 1 galaxy NGC 4051 in 2009 revealed an unusually rich absorption spectrum with outflow velocities, in both Reflection Grating Spectrometers and EPIC spectra, up to ∼9000 km s-1. Evidence was again seen for a fast ionized wind with velocity ∼0.12c. Detailed modelling with the XSTAR photoio…
Mass, shape and thermal properties of Abell 1689 using a multiwavelength X-ray, lensing and Sunyaev-Zel'dovich analysis
Umetsu, Keiichi; Sereno, Mauro; Ettori, Stefano +1 more
Knowledge of the mass and concentration of galaxy clusters is crucial for an understanding of their formation and evolution. Unbiased estimates require an understanding of the shape and orientation of the halo as well as its equilibrium status. We propose a novel method to determine the intrinsic properties of galaxy clusters from a multiwavelengt…
Distant galaxy clusters in the XMM Large Scale Structure survey
Chiappetti, L.; Valtchanov, I.; Ilbert, O. +12 more
Distant galaxy clusters provide important tests of the growth of large-scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look-back time. We present a sample of 22 distant (z > 0.8) galaxy clusters and cluster candidates selected from the 9 deg2 footprint of the …
Ripple effects and oscillations in the broad Fe Kα line as a probe of massive black hole mergers
Haiman, Z.; Ford, K. E. S.; McKernan, B. +1 more
When a sufficiently massive satellite (or secondary) black hole is embedded in a gas disc around a (primary) supermassive black hole, it can open an empty gap in the disc. A gap-opening secondary close to the primary will leave an imprint in the broad component of the Fe Kα emission line, which varies in a unique and predictable manner. If the gap…
The UV/optical spectra of the Type Ia supernova SN 2010jn: a bright supernova with outer layers rich in iron-group elements
Gal-Yam, A.; Kulkarni, S. R.; Sullivan, M. +19 more
Radiative transfer studies of Type Ia supernovae (SNe Ia) hold the promise of constraining both the density profile of the SN ejecta and its stratification by element abundance which, in turn, may discriminate between different explosion mechanisms and progenitor classes. Here we analyse the Type Ia SN 2010jn (PTF10ygu) in detail, presenting and e…
The unbiased measurement of ultraviolet spectral slopes in low-luminosity galaxies at z ≈ 7
McLure, R. J.; Dunlop, J. S.; Rogers, A. B.
The ultraviolet (UV) continuum slope β, typically observed at z ≈ 7 in Hubble Space Telescope (HST) WFC3/IR bands via the J - H colour, is a useful indicator of the age, metallicity and dust content of high-redshift stellar populations. Recent studies have shown that the redward evolution of β with cosmic time from redshift 7 to 4 can be largely e…
Deep luminosity functions and colour-magnitude relations for cluster galaxies at 0.2 < z < 0.6
Bremer, M. N.; De Propris, R.; Phillipps, S.
We derive deep I-band luminosity functions and colour-magnitude diagrams from Hubble Space Telescope imaging for eleven 0.2 < z < 0.6 clusters observed at various stages of merging, and a comparison sample of five more relaxed clusters at similar redshifts. The characteristic magnitude M* evolves passively out to z = 0.6, while the faint-end…
The size of the X-ray emitting region in SWIFT J2127.4+5654 via a broad line region cloud X-ray eclipse
Fabian, A. C.; Miller, J. M.; Miniutti, G. +4 more
We present results obtained from the time-resolved X-ray spectral analysis of the Narrow-Line-Seyfert 1 galaxy SWIFT J2127.4+5654 during a ∼130 ks XMM-Newton observation. We reveal large spectral variations, especially during the first ∼90 ks of the XMM-Newton exposure. The spectral variability can be attributed to a partial eclipse of the X-ray s…