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A long 280 ks observation of the Seyfert 1 galaxy NGC 3783 with XMM-Newton isreported. We focus on the oxygen line complex between 17 and 24 A as measuredwith the RGS spectrometers. Accurate absorption column densities and emissionline fluxes are obtained. We explore several options for the geometry andphysical form of the emitting and absorbing gas. The lack of change inionization in the absorber despite an increase in continuum flux during theobservation 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 thecentral source. Given the P-Cygni type profiles in the resonance spectral linesand the similar velocity widths, column densities, and ionization structureinferred separately from the emission and absorption lines, it is tempting torelate 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 > 10 pc) are consistent with theobservation independent of this assumption. These findings are in starkcontrast with the picture of numerous clumpy (n_e > 10^9 cm^-3) clouds drawnrecently from UV spectra, but it is consistent with the extended X-ray emissioncones observed directly in Seyfert 2 galaxies.Comment: To be published in Ap

A Long Look at NGC 3783 with theXMM‐NewtonReflection Grating Spectrometer