Thomson Reuters NEW YORK (Reuters) - Twenty-First Century Fox Inc is in talks with Blackstone Group LP about submitting an offer to buy Tribune Media Co, one of the largest U.S. television station operators, sources familiar with the matter said on Sunday. Blackstone, the largest manager of private equity and real estate assets, would provide the cash, while Fox, the owner of Fox News Channel and other assets, would provide the TV stations for the joint venture, according to one of the sources. Another source, also speaking on condition of anonymity, said bids are due on Thursday. Representatives for Tribune Media and Blackstone declined to comment.