28 U.S.C. App. (FEDERAL RULES OF APPELLATE PROCEDURE) Rule 48

(a) Appointment; Powers. A court of appeals may appoint a special master to hold hearings, if necessary, and to recommend factual findings and disposition in matters ancillary to proceedings in the court. Unless the order referring a matter to a master specifies or limits the master’s powers, those powers include, but are not limited to, the following: (1) regulating all aspects of a hearing; (2) taking all appropriate action for the efficient performance of the master’s duties under the order; (3) requiring the production of evidence on all matters embraced in the reference; and (4) administering oaths and examining witnesses and parties. (b) Compensation. If the master is not a judge or court employee, the court must determine the master’s compensation and whether the cost is to be charged to any party.