There is a strong spatial correlation between brightest cluster galaxies ( BCGs ) and the peak density and cooling rate of the intra-cluster medium ( ICM ) .
In this paper we combine integral field spectroscopy , CO observations and X-ray data to study three exceptional clusters ( Abell 1991 , Abell 3444 and Ophiuchus ) where there is a physical and dynamical offset between the BCG and the cooling peak to investigate the connection between the cooling of the intracluster medium , the cold gas being deposited and the central galaxy .
We find the majority of the optical line emission is spatially coincident with the peak in the soft X-rays .
In the case of A1991 we make separate detections of CO ( 2-1 ) emission on the BCG and on the peak of the soft X-ray emission suggesting that cooling continues to occur in the core despite being offset from the BCG .
We conclude that there is a causal link between the lowest temperature ( < 2 keV ) ICM gas and the molecular gas ( \sim 30 K ) .
This link is only apparent in systems where a transitory event has decoupled the BCG from the soft X-ray peak .
We discuss the prospects for identifying more examples of this rare configuration .