Search Publications
On characterizing the variability properties of X-ray light curves from active galaxies
Vaughan, S.; Uttley, P.; Warwick, R. S. +1 more
We review some practical aspects of measuring the amplitude of variability in `red noise' light curves typical of those from active galactic nuclei (AGN). The quantities commonly used to estimate the variability amplitude in AGN light curves, such as the fractional rms variability amplitude, Fvar, and excess variance, σ2…
A high-velocity ionized outflow and XUV photosphere in the narrow emission line quasar PG1211+143
O'Brien, P. T.; King, A. R.; Reeves, J. N. +3 more
We report on the analysis of a ~60-ks XMM-Newton observation of the bright, narrow emission line quasar PG1211+143. Absorption lines are seen in both European Photon Imaging Camera and Reflection Grating Spectrometer spectra corresponding to H- and He-like ions of Fe, S, Mg, Ne, O, N and C. The observed line energies indicate an ionized outflow ve…
The iron line in MCG-6-30-15 from XMM-Newton: evidence for gravitational light bending?
Vaughan, S.; Fabian, A. C.
The lack of variability of the broad iron line seen in the Seyfert 1 galaxy MCG-6-30-15 is studied using the EPIC pn data obtained from a 2001 observation of 325 ks, during which the count rate from the source varied by a factor of 5. The spectrum of 80 ks of data from when the source was bright, using the lowest 10 ks as background, is well fitte…
Evidence of a high-velocity ionized outflow in a second narrow-line quasar PG 0844+349
O'Brien, P. T.; King, A. R.; Page, K. L. +1 more
Following the discovery of X-ray absorption in a high-velocity outflow from the bright quasar PG 1211 + 143 we have searched for similar features in XMM-Newton archival data of a second (high accretion rate) quasar PG 0844+349. Evidence is found for several faint absorption lines in both the EPIC and RGS spectra, whose most likely identification w…
An XMM-Newton hard X-ray survey of ultraluminous infrared galaxies
Cappi, M.; Franceschini, A.; Bassani, L. +8 more
XMM-Newton observations of 10 ultraluminous infrared galaxies (ULIRGs) from a 200-ks mini-survey programme are reported. The aim is to investigate in hard X-rays a complete ULIRG sample selected from the bright IRAS 60-µm catalogue. All sources are detected in X-rays, five of which for the first time. These observations confirm that ULIRGs a…
X-ray continuum variability of MCG-6-30-15
Nandra, K.; Vaughan, S.; Fabian, A. C.
This paper presents a comprehensive examination of the X-ray continuum variability of the bright Seyfert 1 galaxy MCG-6-30-15. The source clearly shows the strong, linear correlation between rms variability amplitude and flux first seen in Galactic X-ray binaries. The high-frequency power spectral density (PSD) of MCG-6-30-15 is examined in detail…
Iron and nickel line properties in the X-ray-reflecting region of the Circinus galaxy
Bianchi, Stefano; Matt, Giorgio; Molendi, Silvano
We discuss the iron and nickel properties in the nuclear X-ray-reflecting region of the Circinus galaxy, studied with XMM-Newton. The main results are as follows. (i) From the depth of the Fe Kα edge, a value of AFe= 1.7 in number with respect to the cosmic value (as for Anders & Grevesse) is measured, if the (not directly visible) …
XMM-Newton observations of the hot-gas atmospheres of 3C 66B and 3C 449
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +1 more
We present new XMM-Newton observations of the hot-gas environments of two low-power twin-jet radio galaxies, 3C 66B and 3C 449, showing direct evidence for the interactions between X-ray-emitting gas and radio plasma that are thought to determine the large-scale radio structure of these sources. The temperatures that we measure for the two environ…
XMM-Newton spectral properties of the narrow-line Seyfert 1 galaxy IRAS 13224 - 3809
Brandt, W. N.; Vaughan, S.; Boller, Th. +5 more
We report on the first XMM-Newton observation of the highly X-ray variable, radio-quiet, narrow-line Seyfert 1 galaxy IRAS 13224 - 3809 obtained during the guaranteed time programme with a 64-ks exposure. The most remarkable spectral feature is a sharp drop, by a factor of ~5, in the spectrum at 8 keV. This is a similar, but stronger, feature to t…
The properties of the absorbing and line-emitting material in IGR J16318 - 4848
Guainazzi, Matteo; Matt, Giorgio
We have performed a detailed analysis of the XMM-Newton observation of IGR J16318-4848, to study the properties of the matter responsible for the obscuration and for the emission of Fe and Ni lines. Even if the line-of-sight material has a column density of about 2 × 1024 cm-2, from the Fe Kα line EW and Compton Shoulder we a…