I am working on writing a custom Lightning component for use in a Community. What I need it to do is basically recreate the "Articles with this Topic" default component that goes on the Topic Detail page. The default component doesn't allow for custom sorting or custom messaging based on criteria such as the number of articles in the list or if the Topic is linked to another object record, so I am writing my own that will allow for these things.

I am getting stuck on querying the TopicAssignment object in the Apex controller, which I think must be a permissions issue. When I view the component as myself (System Administrator profile) it appears to work, and I get the list of Knowledge articles. When I log in as a Community User (Customer Community User profile), the Apex method returns an empty list. The code for that Apex method is listed below:

public static List<Knowledge__kav> getArticlesForTopic(String topicId)
	{
		try
		{ 
			return [SELECT Id, Title, Subtitle__c, Article_Body__c FROM Knowledge__kav WHERE Id IN (SELECT EntityId FROM TopicAssignment WHERE TopicId = :topicId) AND PublishStatus = 'Online' ORDER BY Sequence__c ASC, LastPublishedDate DESC]; 
		}
		catch(QueryException qe)
		{
			return null;
		}
		catch(Exception e)
		{
			System.debug(JRBRepo.handleError(e,TRUE));
			return null;
		}
	}

I cannot find the Topic or TopicAssignment objects through the Object Manager UI, so I cannot see a way to grant permissions to these objects for the Community User profile. I see under the System Permissions section that there are several permissions related to managing Topics, but not one for just reading Topics. I don't want the Community Users to have control over Topics or the assignment of Topics, I just need them to be able to read them.

Is there a permission that I am missing, or are those objects named something different in the Object Manager UI?