What is our authority to review a decision by a federal court to confirm or vacate an arbitration award de novo?

"We review a district court's decision to confirm or vacate an arbitration award de novo on questions of law and for clear error on findings of fact." Nat'l Football League Mgmt. Council v. Nat'l Football League Players Ass'n , 820 F.3d 527, 536 (2d Cir. 2016). Our authority to review a labor arbitration award is "narrowly circumscribed and highly deferential." Id. at 532. We may not "review the arbitrator's decision on the merits," but "inquire only as to whether the arbitrator acted within the scope of his authority as defined by the collective bargaining agreement." Id. at 536. "We review a determination of an agency relationship de novo ." Am. Bureau of Shipping v. Tencara Shipyard S.P.A. , 170 F.3d 349, 353 (2d Cir. 1999).

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