We present a multi-wavelength photometric and spectroscopic study of 42 Brightest Cluster Galaxies ( BCGs ) in two samples of galaxy clusters chosen for a gravitational lensing study .
The study ’ s initial sample combines 25 BCGs from the Cluster Lensing and Supernova Survey with Hubble ( CLASH ) sample and 37 BCGs from the Sloan Giant Arcs Survey ( SGAS ) with a total redshift range of 0.2 < z < 0.7 Using archival GALEX , Hubble Space Telescope , Wide- Field Infrared Survey Explorer , Herschel , and Very Large Array data we determine the BCGs ’ stellar mass , radio power , and star formation rates .
The radio power is higher than expected if due to star formation , consistent with the BCGs being active galactic nucleus ( AGN ) -powered radio sources .
This suggests that the AGN and star formation are both fueled by cold gas in the host galaxy .
The specific star formation rate ( sSFR ) is low and constant with redshift .
The mean sSFR is 9.42 \times 10 ^ { -12 } yr ^ { -1 } , which corresponds to a mass doubling time of 105 billion years .
These findings are consistent with models for hierarchical formation of BCGs , which suggest that star formation is no longer a significant channel for galaxy growth for z \leq 1 .
Instead , stellar growth ( of the order of a factor of at least two ) during this period is expected to occur mainly via minor dry mergers .