A long 280 ks observation of the Seyfert 1 galaxy NGC 3783 with XMM-Newton is reported .
We focus on the oxygen line complex between 17 and 24 Å as measured with the RGS spectrometers .
Accurate absorption column densities and emission line fluxes are obtained .
We explore several options for the geometry and physical form of the emitting and absorbing gas .
The lack of change in ionization in the absorber despite an increase in continuum flux during the observation restricts the high-ionization ( O-K ) and the low-ionization ( Fe-M ) gas to distances of at least 0.5 pc and 2.8 pc , respectively , away from the central source .
Given the P-Cygni type profiles in the resonance spectral lines and the similar velocity widths , column densities , and ionization structure inferred separately from the emission and absorption lines , it is tempting to relate the X-ray narrow-line emitting plasma with the X-ray absorbing gas .
Under this assumption , the scenario of dense clumped clouds can be ruled out .
Conversely , extended ionization cones ( r \gtrsim 10 pc ) are consistent with the observation independent of this assumption .
These findings are in stark contrast with the picture of numerous clumpy ( n _ { e } \gtrsim 10 ^ { 9 } cm ^ { -3 } ) clouds drawn recently from UV spectra , but it is consistent with the extended X-ray emission cones observed directly in Seyfert 2 galaxies .