We conduct a deep mid-infrared census of nine massive galaxy clusters at ( 0 < z < 1.3 ) with a total of \sim 1500 spectroscopically confirmed member galaxies using Spitzer /IRAC photometry and established mid-infrared color selection techniques .
Of the 949 cluster galaxies that are detected in at least three of the four IRAC channels at the \geq 3 \sigma level , we identify 12 that host mid-infrared selected active galactic nuclei ( IR-AGN ) .
To compare the IR-AGN across our redshift range , we define two complete samples of cluster galaxies : ( 1 ) optically-selected members with rest-frame V _ { \mathrm { AB } } magnitude < -21.5 and ( 2 ) mid-IR selected members brighter than ( \mathrm { M } ^ { * } _ { 3.6 } +0.5 ) , i.e .
essentially a stellar mass cut .
In both samples , we measure f _ { \mathrm { IR - AGN } } \sim 1 % with a strong upper limit of \sim 3 % at z < 1 .
This uniformly low IR-AGN fraction at z < 1 is surprising given the fraction of 24 \mu m sources in the same galaxy clusters is observed to increase by about a factor of four from z \sim 0 to z \sim 1 ; this indicates that most of the detected 24 \mu m flux is due to star formation .
Only in our single galaxy cluster at z = 1.24 is the IR-AGN fraction measurably higher at \sim 15 % ( all members ; \sim 70 % for late-types only ) .
In agreement with recent studies , we find the cluster IR-AGN are predominantly hosted by late-type galaxies with blue optical colors , i.e .
members with recent/ongoing star formation .
The four brightest IR-AGN are also X-ray sources ; these IR+X-ray AGN all lie outside the cluster core ( R _ { proj } \gtrsim 0.5 Mpc ) and are hosted by highly morphologically disturbed members .
Although our sample is limited , our results suggest that f _ { \mathrm { IR - AGN } } in massive galaxy clusters is not strongly correlated with star formation at z < 1 , and that IR-AGN have a more prominent role at z \gtrsim 1 .