We present the analysis of the XMM- Newton EPIC pn spectrum of the Seyfert 2 galaxy , Mrk 3 .
We confirm that the source is dominated by a pure Compton reflection component and an iron K \alpha line , both produced as reflection from a Compton-thick torus , likely responsible also for the large column density ( 1.36 ^ { +0.03 } _ { -0.04 } \times 10 ^ { 24 } cm ^ { -2 } ) which is pierced by the primary powerlaw only at high energies .
A low inclination angle and an iron underabundance of a factor \simeq 0.82 , suggested by the amount of reflection and the depth of the iron edge , are consistent with the iron K \alpha line EW with respect to the Compton reflection component , being 610 ^ { +30 } _ { -50 } eV .
Moreover , the iron line width , \sigma = 32 ^ { +13 } _ { -14 } eV , if interpreted in terms of Doppler broadening due to the Keplerian rotation of the torus , puts an estimate to the inner radius of the latter , r = 0.6 ^ { +1.3 } _ { -0.3 } \sin ^ { 2 } { i } pc .
Finally , two different photoionised reflectors are needed to take into account a large number of soft X-ray emission lines from N , O , Ne , Mg , Si , Fe L and the Fe xxv emission line at 6.71 ^ { +0.03 } _ { -0.02 } keV .
RGS spectra show that the soft X-ray spectrum is dominated by emission lines , while the underlying continuum is best fitted by an unabsorbed powerlaw with the same photon index of the primary continuum , produced as reflection by a photoionised material with a column density of a few 10 ^ { 22 } cm ^ { -2 } .
We also present the first X-ray spectrum of ROSAT source IXO 30 , which shows a huge iron line at 6.5 ^ { +0.3 } _ { -0.2 } keV and is well represented either by an absorbed powerlaw with \Gamma \simeq 1.8 or bremsstrahlung emission at a temperature of 7.5 ^ { +2.1 } _ { -1.6 } keV .
Its spectral properties point to a likely identification in terms of a weak Galactic Cataclysmic Variable , but the lack of any optical counterpart precludes excluding other possibilities , like an ULX at the distance of Mrk 3 .