We explore 7.5 billion years of evolution in the star formation activity of massive ( M _ { \star } > 10 ^ { 10.1 } M _ { \odot } ) cluster galaxies using a sample of 25 clusters over 0.15 < z < 1 from the Cluster Lensing And Supernova survey with Hubble and 11 clusters over 1 < z < 1.5 from the IRAC Shallow Cluster Survey .
Galaxy morphologies are determined visually using high-resolution Hubble Space Telescope images .
Using the spectral energy distribution fitting code CIGALE , we measure star formation rates , stellar masses , and 4000 Å break strengths .
The latter are used to separate quiescent and star-forming galaxies ( SFGs ) .
From z \sim 1.3 to z \sim 0.2 , the specific star formation rate ( sSFR ) of cluster SFGs and quiescent galaxies decreases by factors of three and four , respectively .
Over the same redshift range , the sSFR of the entire cluster population declines by a factor of 11 , from 0.48 \pm 0.06 \mathrm { Gyr } ^ { -1 } to 0.043 \pm 0.009 \mathrm { Gyr } ^ { -1 } .
This strong overall sSFR evolution is driven by the growth of the quiescent population over time ; the fraction of quiescent cluster galaxies increases from 28 ^ { +8 } _ { -19 } \% to 88 ^ { +5 } _ { -4 } \% over z \sim 1.3 \rightarrow 0.2 .
The majority of the growth occurs at z \gtrsim 0.9 , where the quiescent fraction increases by 0.41 .
While the sSFR of the majority of star-forming cluster galaxies is at the level of the field , a small subset of cluster SFGs have low field-relative star formation activity , suggestive of long-timescale quenching .
The large increase in the fraction of quiescent galaxies above z \sim 0.9 , coupled with the field-level sSFRs of cluster SFGs , suggests that higher redshift cluster galaxies are likely being quenched quickly .
Assessing those timescales will require more accurate stellar population ages and star formation histories .