Appeal to authority
Argumentum ad verecundiam: deductively fallacious; even legitimate authorities speaking on their areas of expertise may affirm a falsehood.
However, if not using a deductive argument, a logical fallacy is only asserted when the source is not a legitimate expert on the topic at hand, or their conclusion(s) are in direct opposition to other expert consensus. Appeal to authority does not condone to agreeing to the argument. n