We investigate the evolution of star formation rates ( SFRs ) , stellar masses , and M/L _ { 3.4 \micron } ratios of brightest cluster galaxies ( BCGs ) in the COSMOS survey since z \sim 1 to determine the contribution of star formation to the growth-rate of BCG stellar mass over time .
Through the spectral energy distribution ( SED ) fitting of the GALEX , CFHT , Subaru , Vista , Spitzer , and Herschel photometric data available in the COSMOS2015 catalog , we estimate the stellar mass and SFR of each BCG .
We use a modified version of the iSEDfit package to fit the SEDs of our sample with both stellar and dust emission models , as well as constrain the impact of star formation history assumptions on our results .
We find that in our sample of COSMOS BCGs , star formation evolves similarly to that in BCGs in samples of more massive galaxy clusters .
However , compared to the latter , the magnitude of star formation in our sample is lower by \sim 1 dex .
Additionally , we find an evolution of BCG baryonic mass-to-light ratio ( M / L _ { 3.4 \mu m } ) with redshift which is consistent with a passively aging stellar population .
We use this to build upon ’ s low-redshift \nu L _ { 3.4 \micron } - M _ { Stellar } relation , quantifying a correlation between \nu L _ { 3.4 \micron } and M _ { Stellar } to z \sim 1 .
By comparing our results to BCGs in Sunyaev–Zel ’ dovich and X-ray-selected samples of galaxy clusters , we find evidence that the normalization of star formation evolution in a cluster sample is driven by the mass range of the sample and may be biased upwards by cool cores .