Search Publications
Is the black hole in NGC 1277 really overmassive?
Emsellem, Eric
A recent claim has been made by van den Bosch et al. that the fast-rotator galaxy NGC 1277 hosts an overmassive black hole with a mass (1.7 × 1010 M⊙) larger than half its (central) stellar spheroid mass. We revisit this claim here by examining the predictions from simple dynamical realizations based on new multi-Gaussian exp…
First X-ray evidence for a shock at the Coma relic
Brüggen, M.; Ogrean, G. A.
The Coma cluster is one of the nearest galaxy clusters, and the first one in which a peripheral radio relic was discovered. However, X-ray observations of the plasma near the relic have been scarce. Here, we present results from a re-analysis of a 22 ks archival XMM-Newton observation. Across the relic, we detect a temperature discontinuity indica…
Herschel reveals the obscured star formation in HiZELS Hα emitters at z = 1.47
Smail, I.; Berta, S.; Magnelli, B. +28 more
We describe the far-infrared (far-IR; rest-frame 8-1000-µm) properties of a sample of 443 Hα-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with…
H-ATLAS: estimating redshifts of Herschel sources from sub-mm fluxes
Valtchanov, I.; Ivison, R. J.; Scott, D. +29 more
Upon its completion, the Herschel Astrophysics Terahertz Large Area Survey (H-ATLAS) will be the largest sub-millimetre survey to date, detecting close to half-a-million sources. It will only be possible to measure spectroscopic redshifts for a small fraction of these sources. However, if the rest-frame spectral energy distribution (SED) of a typi…
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…