Multi-wavelength campaign on NGC7469 I. The rich 640 ks RGS spectrum
  Outflows in active galaxies (AGNs) are common, although their launching
mechanism, location, and physical impact on the host galaxy remain
controversial. We conducted a multiwavelength six-month campaign to observe the
nearby Seyfert galaxy NGC 7469 with several observatories in order to better
understand and quantify the outflow in this AGN. We report on the
time-integrated line-resolved X-ray spectrum of NGC 7469 obtained with the
Reflection Grating Spectrometer (RGS) on board XMM-Newton. We use the RGS
spectrum to discern the many AGN outflow components. A global fit is applied to
obtain their physical parameters. We find that the AGN wind can be well
described by three narrow velocity components at -650, -950, and -2050 km/s.
The RGS clearly resolves the -20 50 km/s component in C5+ Ly$\alpha$, while the
-650 km/s and -950 km/s velocities are blended. Similar velocities are resolved
in the UV. The H-equivalent column densities of these components are,
respectively, NH = 7x10^20, 2.2x10^21, and 10^20 cm^-2, for a total of 3x10^21
cm^-2. The -650 km/s component shows a broad ionisation distribution. We
identify a photo-ionised emission component blue-shifted by -450 km/s which we
ascribe to the same outflow that produces the absorption lines. The elemental
abundance ratios of C, N, Ne, S, and Fe to O in the outflow tend to be between
1 - 2 times solar. Preliminary estimates of the absorber distance from the AGN
center suggest it is at least a few pc away from the center, but more advanced
methods need to be applied in order to obtain better constraints. The complex
X-ray spectrum of NGC 7469 demonstrates the richness of high energy phenomena
taking place in AGN cores. The subtle spectroscopic differences between the
various components require deep, high-resolution observations, such as the
present RGS spectrum, if one is to resolve them and perform quantitative plasma
diagnostics.
