We explore the redshift evolution of a curious correlation between the star-formation properties of central galaxies and their satellites ( ‘ galactic conformity ’ ) at intermediate to high redshift ( 0.4 < z < 1.9 ) .
Using an extremely deep near-infrared survey , we study the distribution and properties of satellite galaxies with stellar masses , { log } ( { M } _ { * } / { M } _ { \odot } ) > 9.7 , around central galaxies at the characteristic Schechter function mass , { M } \sim { M } ^ { \ast } .
We fit the radial profiles of satellite number densities with simple power laws , finding slopes in the range -1.1 to -1.4 for mass-selected satellites , and -1.3 to -1.6 for passive satellites .
We confirm the tendency for passive satellites to be preferentially located around passive central galaxies at 3 \sigma significance and show that it exists to at least z \sim 2 .
Meanwhile , the quenched fraction of satellites around star-forming galaxies is consistent with field galaxies of equal stellar masses .
We find no convincing evidence for a redshift-dependent evolution of these trends .
One simple interpretation of these results is that only passive central galaxies occupy an environment that is capable of independently shutting off star-formation in satellite galaxies .
By examining the satellites of higher stellar mass star-forming galaxies ( { log } ( { M } _ { * } / { M } _ { \odot } ) > 11 ) , we conclude that the origin of galactic conformity is unlikely to be exclusively due to the host dark-matter halo mass .
A halo-mass-independent correlation could be established by either formation bias or a more physical connection between central and satellite star-formation histories .
For the latter , we argue that a star-formation ( or AGN ) related outburst event from the central galaxy could establish a hot halo environment which is then capable of quenching both central and satellite galaxies .