The cross-correlation of redshited 21-cm signal and Lyman-α forest: A cosmological probe

We have investigated the cross-correlation of the Lyman-α forest and redshifted 21-cm emission as a new observational probe of the large scale structures in the post-reionization era, with a significant advantage that the problems of continuum subtraction and foreground removal, and other systematics are expected to be considerably less servere in comparison to the respective auto-correlation signals. In this paper, we have explored the possibility of detecting the baryon acoustic oscillation in the cross-correlation signal. We have developed a formalism to calculate the expected cross-correlation signal and its covariance. We have used this to predict the expected signal and noise for a range of observational parameters