Search Publications
A shock front at the radio relic of Abell 2744
Kneib, J. -P.; Eckert, D.; Vazza, F. +5 more
Radio relics are Mpc-scale diffuse radio sources at the peripheries of galaxy clusters which are thought to trace outgoing merger shocks. We present XMM-Newton and Suzaku observations of the galaxy cluster Abell 2744 (z = 0.306), which reveal the presence of a shock front 1.5 Mpc east of the cluster core. The surface-brightness jump coincides with…
A comprehensive analysis of the hard X-ray spectra of bright Seyfert galaxies
Papadakis, I. E.; Paltani, S.; Walter, R. +7 more
Hard X-ray spectra of 28 bright Seyfert galaxies observed with INTEGRAL were analysed together with the X-ray spectra from XMM-Newton, Suzaku and RXTE. These broad-band data were fitted with a model assuming a thermal Comptonization as a primary continuum component. We tested several model options through a fitting of the Comptonized continuum acc…
Short-term X-ray spectral variability of the quasar PDS 456 observed in a low-flux state
Tombesi, F.; Reeves, J. N.; Braito, V. +4 more
We present a detailed analysis of a recent, 2013 Suzaku campaign on the nearby (z = 0.184) luminous (Lbol ∼ 1047 erg s-1) quasar PDS 456. This consisted of three observations, covering a total duration of ∼1 Ms and a net exposure of 455 ks. During these observations, the X-ray flux was unusually low, suppressed by …
Revealing the accretion disc corona in Mrk 335 with multi-epoch X-ray spectroscopy
Ballantyne, D. R.; Keek, L.
Active galactic nuclei host an accretion disc with an X-ray producing corona around a supermassive black hole. In bright sources, such as the Seyfert 1 galaxy Mrk 335, reflection of the coronal emission off the accretion disc has been observed. Reflection produces spectral features such as an Fe Kα emission line, which allow for properties of the …
Suzaku view of the Be/X-ray binary pulsar GX 304-1 during Type I X-ray outbursts
Naik, Sachindra; Jaisawal, Gaurava K.; Epili, Prahlad
We report the timing and spectral properties of the Be/X-ray binary pulsar GX 304-1 using two Suzaku observations during its 2010 August and 2012 January X-ray outbursts. Pulsations at ∼275 s were clearly detected in the light curves from both observations. Pulse profiles were found to be strongly energy-dependent. During the 2010 observation, the…
Galactic Centre hypershell model for the North Polar Spurs
Kataoka, J.; Matsui, H.; Nakashima, S. +5 more
The bipolar-hypershell (BHS) model for the North Polar Spurs (NPS-E, -W, and Loop I) and counter southern spurs (SPS-E and -W) is revisited based on numerical hydrodynamical simulations. Propagations of shock waves produced by energetic explosive events in the Galactic Centre are examined. Distributions of soft X-ray brightness on the sky at 0.25,…
Relativistic Fe Kα line study in Seyfert 1 galaxies observed with Suzaku
Nandra, K.; Ponti, G.; Mantovani, G.
We present an analysis of a sample of Seyfert 1 galaxies observed with Suzaku. The aim of this work is to examine critically the evidence for a relativistic Fe Kα line in the X-ray spectra of these active galactic nuclei. The sample was compiled from those sources in which a relativistic component was missing in at least one XMM-Newton observation…
The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study
Harrison, F.; Stern, D.; Bauer, F. E. +22 more
In this paper, we report the results of an X-ray monitoring campaign on the heavily obscured Seyfert galaxy, Markarian 3, carried out between the fall of 2014 and the spring of 2015 with NuSTAR, Suzaku and XMM-Newton. The hard X-ray spectrum of Markarian 3 is variable on all the time-scales probed by our campaign, down to a few days. The observed …
Ne X X-ray emission due to charge exchange in M82
Liu, L.; Cumbee, R. S.; Lyons, D. +4 more
Recent X-ray observations of star-forming galaxies such as M82 have shown the Ly β/Ly α line ratio of Ne X to be in excess of predictions for thermal electron impact excitation. Here, we demonstrate that the observed line ratio may be due to charge exchange and can be used to constrain the ion kinetic energy to be ≲ 500 eV/u. This is accomplished …
No signatures of black hole spin in the X-ray spectrum of the Seyfert 1 galaxy Fairall 9
Turner, T. J.; Yaqoob, T.; Tatum, M. M. +2 more
Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe Kα emission line and Compton-reflection continuum in the X-ray spectrum. The method rests upon the interpretation of the Fe Kα line profile and associated …