Search Publications
The nature of the Compton-thick X-ray reprocessor in NGC 4945
Yaqoob, Tahir
We present an exhaustive methodology for fitting Compton-thick X-ray reprocessor models to obscured active galactic nuclei (AGNs) and for interpreting the results. We focus on the MYTORUS model but also include some analysis from other models. The models are applied specifically to Suzaku, BeppoSAX and Swift Burst Alert Telescope spectra of the Se…
On the determination of the spin of the black hole in Cyg X-1 from X-ray reflection spectra
Fabian, A. C.; Miller, J. M.; Reynolds, C. S. +9 more
The spin of Cygnus X-1 is measured by fitting reflection models to Suzaku data covering the energy band 0.9-400 keV. The inner radius of the accretion disc is found to lie within 2 gravitational radii (rg=GM/c2), and a value of ? is obtained for the dimensionless black hole spin. This agrees with recent measurements using the…
A Suzaku survey of Fe K lines in Seyfert 1 active galactic nuclei
Porquet, D.; Reeves, J. N.; Braito, V. +3 more
We construct full broad-band models in an analysis of Suzaku observations of nearby Seyfert 1 active galactic nuclei (AGN) (z ≤ 0.2) with exposures >50 ks and with greater than 30 000 counts in order to study their iron line profiles. This results in a sample of 46 objects and 84 observations. After a full modelling of the broad-band Suzaku and…
Observing simulated galaxy clusters with PHOX: a novel X-ray photon simulator
Böhringer, H.; Dolag, K.; Lemson, G. +1 more
We present a novel, virtual X-ray observatory designed to obtain synthetic observations from hydro-numerical simulations, named PHOX. In particular, we provide a description of the code constituting the photon simulator and of the new approach implemented. We apply PHOX to simulated galaxy clusters in order to demonstrate its capabilities. In fact…
Broad-band study of hard X-ray-selected absorbed active galactic nuclei
de Rosa, A.; Ubertini, P.; Landi, R. +6 more
In this paper we report on the broad-band X-ray properties of a complete sample of absorbed Seyfert galaxies hard X-ray selected with INTEGRAL. Our sample is composed of 33 sources, of which 15 are newly discovered active galactic nuclei (AGN) above 20 keV (IGR sources), while 18 are already known type 2 AGN ('known'). For 17 sources (15 IGR + 2 '…
X-ray observations of the galaxy cluster Abell 2029 to the virial radius
Fabian, A. C.; Sanders, J. S.; Walker, S. A. +2 more
We present Suzaku observations of the galaxy cluster Abell 2029, which exploit Suzaku's low particle background to probe the intracluster medium at radii beyond that which is possible with previous observations, and with better azimuthal coverage. We find significant anisotropies in the temperature and entropy profiles, with a region of lower temp…
The X-ray reflector in NGC 4945: a time- and space-resolved portrait
Bianchi, S.; Elvis, M.; Fabbiano, G. +5 more
We present a time, spectral and imaging analysis of the X-ray reflector in NGC 4945, which reveals its geometrical and physical structure with unprecedented detail. NGC 4945 hosts one of the brightest AGN in the sky above 10 keV, but it is only visible through its reflected/scattered emission below 10 keV, due to absorption by a column density of …
A broad iron line in LMC X-1
Steiner, James F.; Reis, Rubens C.; Fabian, Andrew C. +6 more
We present results from a deep Suzaku observation of the black hole in LMC X-1, supplemented by coincident monitoring with the Rossi X-ray Timing Explorer (RXTE). We identify broad relativistic reflection features in a soft disc-dominated spectrum. A strong and variable power-law component of emission is present which we use to demonstrate that en…
Galaxy cluster outskirts: a universal entropy profile for relaxed clusters?
Fabian, A. C.; Sanders, J. S.; Walker, S. A. +1 more
We fit a functional form for a universal intracluster medium entropy profile to the scaled entropy profiles of a catalogue of X-ray galaxy cluster outskirts results, which are all relaxed cool core clusters at redshift below 0.25. We also investigate the functional form suggested by Lapi et al. and Cavaliere et al. for the behaviour of the entropy…
NGC 454: unveiling a new 'changing look' active galactic nucleus
Braito, V.; Caccianiga, A.; Severgnini, P. +2 more
We present a detailed analysis of the X-ray spectrum of the Seyfert 2 galaxy NGC 454E, belonging to the interacting system NGC 454. Observations performed with Suzaku, XMM-Newton and Swift allowed us to detect a dramatic change in the curvature of the 2-10 keV spectrum, revealing a significant variation of the absorbing column density along the li…