Online material

Appendix A: Sources from the flux-limited sample

List of 33 sources in the flux-limited sample. These sources have been selected from the RXTE all-sky Slew Survey (XSS, Revnivtsev et al. 2004) with a count rate in the 3–8 keV energy band greater than 1 cts/sec and fulfilling the FERO source selection criteria. The XSS is nearly 80% complete at the selected flux level for sources with Galactic latitude greater than 10°. For two of them, UGC 10683 and ESO 0141-G055, no XMM-Newton data were available as of April 2008. This leaves the number of XSS-selected bright sources in the FERO sample at 31.

Appendix B: List of sources with multiple observations that have not been summed

List of sources within the FERO sample where multiple observations are available but only one has been used (the one with longest exposure time).

Appendix C: Best-fit-model parameters for sources belonging to the flux-limited sample

Table C.1 gives some relevant best-fit-model parameters (see Sect. 3.3) for the 31 sources belonging to the flux-limited sample.

Appendix D: Relativistic Fe K_α line EW upper limits for the sources in the flux-limited sample

List of 20 sources within the flux-limited sample with an upper limit to the relativistic Fe K_α line EW.

Appendix E: A final self-consistent test on the detections within the flux-limited sample

As a final test, the hard X-ray spectra of all the sources in the flux-limited sample for which a significant detection of the relativistic line can be claimed has been described with the most self-consistent reflection model envisaged, but keeping the model as simple as possible. The baseline model comprises one layer of ionised absorption (the ZXIPCF model), reflection off cold distant matter including the most important emission lines and the associated self-consistent reflection continuum (the PEXMON model), and reflection from the accretion disc (the Ross & Fabian REFLION model, convolved with the KYRLINE kernel). Two ionised emission lines with energies fixed at 6.7 keV and 6.96 keV are also included as in the previous phenomenological models used throughout the paper, although they are not statistically required in all cases.

The PEXMON model is described in detail in Nandra et al. (2007) and describes the reflection spectrum from a cold slab of gas including both the reflection continuum and the most relevant emission lines, which are computed as self-consistently as possible according to the work by George & Fabian (1991). The metal abundances are fixed to the solar value (except for the case of MCG–6-30-15, see below) and the reflector inclination with respect to the line of sight to 60 degrees, which is appropriate for torus-like reflection in Seyfert 1 galaxies. The illuminating continuum is a power law with the same photon index as the power-law component of our spectral model. The REFLION model describes reflection off a ionised slab and is used instead to describe the disc reflection component. The illuminating photon index is the same as the primary continuum and the Fe abundance is fixed to the solar value (except for MCG–6-30-15, see below). The model is convolved with the kernel of the KYRLINE model (Dovčiak et al. 2004), which allows including all relativistic effects and measuring the relevant parameters.

It is important to stress once again that the goal here is not to provide the best possible fitting statistics but rather to compare the results of the phenomenological model used in the paper (which does not account for emission lines and associated reflection continua in a self-consistent manner) with a more physical spectral model. In some cases, more spectral components are included as explained in the subsequent section.

The results are reported in Table E.1, where the most important spectral parameters associated with the reflection components are considered. In Table E.2 the best-fitting relativistic parameters for both the phenomenological and the more physically motivated models are reported. Such a comparison implies that the more complex and self-consistent model for the reflection components does not significantly affect the results. Since the cases considered here correspond to the highest signal-to-noise data within the whole sample, the test supports the analysis carried out on the whole available sample within the context of the less sophisticated and more phenomenological model.

E.1. Notes on individual sources

Slight modifications to the baseline model described in Appendix E are given here for some individual sources. In the remaining cases, the baseline model was applied without being modified. IC 4329A: absorption is best modelled with a neutral layer with moderate column density (≃4 × 10²¹ cm^-2). A Gaussian absorption line with EW ≃  −15 eV was also included to model an absorption feature at  ≃7.65 keV phenomenologically. MCG-5-23-16: absorption is best modelled with a neutral layer with column density N_H ≃ 1.5 × 10²² cm^-2. The presence of a further ionised layer is possible but not statistically required. MCG-6-30-15: the Fe abundance of the two reflectors was left free to vary in this case resulting in an overabundance of  ~  ×  3 with respect to the solar value. The model also comprises a Gaussian absorption line at  ≃ 6.7 keV with EW ≃  − 15 eV. NGC 4051: a Gaussian absorption line with EW ≃  − 30 eV was also included to model an absorption feature at  ≃7.04 keV phenomenologically. NGC 3516: a Gaussian absorption line with EW ≃  − 28 eV was also included to model an absorption feature at  ≃6.7 keV phenomenologically. NGC 3783: a Gaussian absorption line with EW ≃  − 20 eV was also included to model an absorption feature at  ≃6.7 keV phenomenologically. Mrk 509: a Gaussian absorption line with EW ≃  − 10 eV was also included to model an absorption feature at  ≃7.3 keV phenomenologically.

© ESO, 2010