Starbursting to Quenching: the role of X-ray emission in Active Galactic Nuclei feedback processes

 Feedback mechanisms during the bright phase of active galactic nuclei (AGN)
are indicated as the leading processes responsible for the joint evolution of
super-massive black holes (SMBH) and galaxies. We investigate the kinematic and
physical properties of ionized and atomic interstellar medium gas of well
selected AGN-galaxy systems, obtained from UV, optical, near-IR spectroscopic
analysis, to unveil the presence of outflows. In particular, we propose and
test different selection criteria to isolate sources at z~2 in the predicted
feedback phase, starting from multiwavelength information collected in the
COSMOS field. As a complementary approach, we also collect a large sample of
X-ray selected AGNs at z < 0.8 from the SDSS database to unveil the incidence
of outflows and prove the crucial role of X-ray observations for the
investigation of the feedback phase. We study in detail the dynamical
conditions of the ionized outflows of the high-z samples, for which high
spatial resolution data have been obtained. We report the unambiguous presence
of fast, massive outflows in 4 obscured QSOs, extending up to 10 kpc in the
host galaxy and with profound effects on the host galaxy. We carefully discuss
the uncertainties related to the assumption of the plasma conditions in the
estimate of the outflows properties and we report, for the first time, the
plasma electron density and temperature in a mid-size sample of AGNs. Finally,
we combine the ionized/neutral gas kinematic and physical conditions with SMBH
accretion and host galaxy properties to infer the general conditions regulating
the feedback processes. We also discuss our results in the context of recent
observational and theoretical clues.