7 High S/N spectra

In Fig. 10 we show six X-ray spectra representative of the different classes of objects in our sample. The source numbers refer to the catalogue presented in this work, for reference we give also the ROSAT catalogue numbers (Hasinger et al. 1998). The redshift of the sources are reported in Lehmann et al. (2001a). Sources with interesting line features will be reported in a future work (Hasinger et al. 2002, in preparation).

Figure 10: XMM EPIC-pn CCD spectra and best fit models. Top: source $\char93 4$ (ROSAT $\char93 29$) and source $\char93 6$ (ROSAT $\char93 16$); middle: source $\char93 25$ (ROSAT $\char93 84$) and source $\char93 26$ (ROSAT $\char93 117$); bottom: source $\char93 50$ (ROSAT $\char93 901$) and source $\char93 96$ (ROSAT $\char93 39$).

7.1 Unabsorbed sources

Source $\char93 4$ (ROSAT $\char93 29$): this source was already observed by ROSAT (Lehmann et al. 2000) and optically classified as a Type-1 AGN at z=0.784. This is one of the brightest sources in our sample (3164 EPIC-pn counts in the [0.5-7] keV band). This source is very well fitted ( $\chi_\nu^2=1.03$) by a simple power law model with $\Gamma=2.02^{+0.04}_{-0.04}$ and $N_{\rm H}$consistent with the Galactic value ( $5.7\times 10^{19}$ ${\rm cm}^{-2}$). We measure $L_{\rm X} = 4.2\times10^{44}$ erg s^-1 in the [0.5-10] keV rest-frame band, and ${\log (\frac{f_x}{f_R})}=0.6$.

Source $\char93 6$ (ROSAT $\char93 16$): it was observed by ROSAT (Schmidt et al.1998) and classified as a Type-1 AGN at z=0.586. This source (1537 EPIC-pn counts in the [0.5-7] keV band) is well fitted ( $\chi_\nu^2=1.15$) by a simple power law model with $\Gamma=2.47_{-0.03}^{+0.08}$ and $N_{\rm H}$ consistent with the Galactic value ( $5.7\times 10^{19}$  ${\rm cm}^{-2}$). It has $L_{\rm X} = 1.2 \times10^{44}$ erg s^-1 in the [0.5-10] keV rest-frame band.

7.2 Absorbed sources

Source $\char93 25$ (ROSAT $\char93 84$): this object was part of the ROSAT ultradeep HRI survey (Hasinger et al. 1998). Lehmann et al. (2001a) give a photometric redshift $z_{\rm phot}=2.71^{+0.29}_{-0.41}$. The spectrum extracted from the EPIC-pn data (332 counts in the [0.5-7] keV band) is well fitted ( $\chi_\nu^2=1.09$) by a $wabs\ast zwabs(powerlaw)$ model, with an intrinsic absorption of $N_{\rm H}=3^{+1}_{-1}\times10^{23}$  ${\rm cm}^{-2}$ and $\Gamma=2.3^{+0.3}_{-0.3}$; the unabsorbed rest-frame luminosity in the [0.5-10] keV band is $L_{\rm X}=5.49 \times 10^{45}$ erg s^-1.

Source $\char93 26$ (ROSAT $\char93 117$): was observed by ROSAT (Schmidt et al. 1998) and optically classified as a Type-2 AGN at z=0.780. From the fit of the X-ray spectra we get the values, $N_{\rm H}=2^{+1}_{-1}\times10^{22}$ cm^-2 and $\Gamma=1.5^{+0.4}_{-0.3}$. The unabsorbed X-ray luminosity in the [0.5-10] keV rest-frame band is $L_{\rm X}=4 \times 10^{43}$ erg s^-1.

   
7.3 Multi component spectra

Source $\char93 50$ (ROSAT $\char93 901$): this source was classified as a Type-2 AGN at z=0.204 by Lehmann et al. (2001a). As noted in Paper I, a very soft component superimposed on a heavy absorbed power law, is likely present in this source as suggested by the unusually large value of the hardness ratio HR3. The XMM-Newton spectrum clearly shows such a feature. By fitting a double power law model ( wabs(zwabs(powerlaw)+powerlaw)), we obtain: $N_{\rm H}=4^{+2.5}_{-1.5}\times 10^{23}$ cm^-2, $\Gamma=3^{+1}_{-1}$ for the hard component and $\Gamma=3.3^{+0.4}_{-0.5}$ for the soft component ( $\chi_\nu^2=1.2$). We also find an unabsorbed X-ray luminosity $L_{\rm X}=5.7 \times 10^{43}$ erg s^-1 in the [0.5-10] keV rest-frame band and a ratio ${\log~ (\frac{f_{\rm x}}{f_{\rm R}})}=-2.4$, unusually low for an AGN, which is probably due to the strong intrinsic absorption.

   
7.4 Type-1 QSO with X-ray absorption

Source $\char93 96$ (ROSAT $\char93 39$): this object is optically classified as a Type-1 QSO at z=3.279 (Lehmann et al., 2001a). A clear absorption is present in the X-ray spectrum and the fit yields $N_{\rm H}=5^{+5}_{-3}\times 10^{22}$ cm^-2. As already argued in Sect. 3.2, this mismatch between the optical and X-ray classifications could be due to a gas-to-dust ratio or a chemical composition different from that of the Galactic interstellar gas (Akiyama et al. 2000; Maiolino et al. 2001b).