  The central galaxies of some clusters can be strong emitters in the
Ly$\alpha$ and H$\alpha$ lines. This emission may arise either from the
cool/warm gas located in the cool core of the cluster or from the bright AGN
within the central galaxy. The luminosities of such lines can be as high as
$10^{42} - 10^{44}$ erg/s. This emission originating from the core of the
cluster will get Thomson scattered by hot electrons of the intra-cluster medium
(ICM) with an optical depth $\sim$ 0.01 giving rise to very broad ($\Delta
\lambda / \lambda \sim$ 15%) features in the scattered spectrum. We discuss the
possibility of measuring the electron density and temperature using information
on the flux and width of the highly broadened line features.
