Is Ray a valid Irish name

My earliest relative is Mathias Ray from Limrick. He landed in Conneticut in the 1840's. Is ray correct or a varient of some other name?

Yes and No. MacLysaght says Ray is an English name same as Roy derived from Roi the French for King. But the surnames Reavey, Rea and Wray were sometimes corrupted to Ray. Rea is pronounced Ray in Ireland and derives from the Irish MacCrea, Reavey comes from the Irish MacRiabhaigh (grey haired) anglicised to MacGreevey. So you can safely claim to be Irish with a corrupted surname.