Abstract
Dwarf galaxies are ideal laboratories to study the relationship between the
environment and AGN activity. However, the type of environments in which dwarf
galaxies hosting AGN reside is still unclear and limited to low-redshift
studies (z < 0.5). We use the VIMOS Public Extragalactic Redshift Survey
(VIPERS) to investigate, for the first time, their environments at 0.5 < z <
0.9. We select a sample of 12,942 low-mass
($log(M_*/M_ødot)łeq10$) galaxies and use the emission-line
diagnostic diagram to identify AGN. We characterise their local environments as
the galaxy density contrast, $\delta$, derived from the fifth nearest neighbour
method. Our work demonstrates that AGN and non-AGN dwarf galaxies reside in
similar environments at intermediate redshift suggesting that the environment
is not an important factor in triggering AGN activity already since z = 0.9.
Dwarf galaxies show a strong preference for low-density environments,
independently of whether they host an AGN or not. Their properties do not
change when moving to denser environments, suggesting that dwarf galaxies are
not gas-enriched due to environmental effects. Moreover, AGN presence does not
alter host properties supporting the scenario that AGN feedback does not impact
the star formation of the host. Lastly, AGN are found to host over-massive
black holes. This is the first study of dwarf galaxies hosting AGN at z > 0.5.
The next generation of deep surveys will reveal whether or not such lack of
environmental trends is common also for faint higher-redshift dwarf galaxy
populations.
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