The VIMOS Public Extragalactic Redshift Survey (VIPERS). AGN feedback in
  [NeV] emitters
  Using an unconventional single line diagnostic that unambiguously identifies
AGNs in composite galaxies we report statistical differences in the properties
(stellar age, [OII] luminosity, colour) between active and inactive galaxies at
0.62<z<1.2 extracted from the VIMOS Public Extragalactic Redshift Survey
(VIPERS). The nuclear activity is probed by the high-ionization [NeV] emission
line and along with their parent samples, the galaxies are properly selected
according to their stellar mass, redshift, and colour distributions. We report
younger underlying stellar ages and higher [OII] luminosities of active
galaxies in the green valley and in the blue cloud compared to control samples.
We observe higher fractions of green galaxies hosting AGN activity at
progressively bluer (r-K) colours. Depending on the location of the host galaxy
in the NUVrK colour diagram we find higher AGN fractions in massive blue
galaxies and in the least massive red galaxies, in agreement with the picture
that black holes vary their properties when hosted in either star-forming or
passive galaxies. Exactly where the fast quenching processes are expected to
play a role, we identify a novel class of active galaxies in the blue cloud
with signatures typical for a suddenly suppression of their star formation
activity after a burst happening in the recent past. Their optical spectra
resemble those of post-starburst galaxies, that would never be identified in a
spectroscopic search using classical selection techniques. Broadly, these
active galaxies selected on the [NeV] line are not commonly represented in
shallow X-ray, mid-IR, or classical line diagnostics. If we consider that our
results are limited by the shallow observational limits and rapid AGN
variability, the impact of AGN feedback on galaxy formation and evolution may
represent an important channel of fast-transiting galaxies moving to the red
sequence.
