Satellite Quenching and Galactic Conformity at 0.3 < z < 2.5
  We measure the evolution of the quiescent fraction and quenching efficiency
of satellites around star-forming and quiescent central galaxies with stellar
mass $\log(M_{\mathrm{cen}}/M_{\odot})>10.5$ at $0.3<z<2.5$. We combine imaging
from three deep near-infrared-selected surveys (ZFOURGE/CANDELS, UDS, and
UltraVISTA), which allows us to select a stellar-mass complete sample of
satellites with $\log(M_{\mathrm{sat}}/M_{\odot})>9.3$. Satellites for both
star-forming and quiescent central galaxies have higher quiescent fractions
compared to field galaxies matched in stellar mass at all redshifts. We also
observe "galactic conformity": satellites around quiescent centrals are more
likely to be quenched compared to the satellites around star-forming centrals.
In our sample, this conformity signal is significant at $\gtrsim3\sigma$ for
$0.6<z<1.6$, whereas it is only weakly significant at $0.3<z<0.6$ and
$1.6<z<2.5$. Therefore, conformity (and therefore satellite quenching) has been
present for a significant fraction of the age of the universe. The satellite
quenching efficiency increases with increasing stellar mass of the central, but
does not appear to depend on the stellar mass of the satellite to the mass
limit of our sample. When we compare the satellite quenching efficiency of
star-forming centrals with stellar masses 0.2 dex higher than quiescent
centrals (which should account for any difference in halo mass), the conformity
signal decreases, but remains statistically significant at $0.6<z<0.9$. This is
evidence that satellite quenching is connected to the star-formation properties
of the central as well as to the mass of the halo. We discuss physical effects
that may contribute to galactic conformity, and emphasize that they must allow
for continued star-formation in the central galaxy even as the satellites are
quenched.
