Either they were restored from backups of published databases or there was replication at one point and it was removed improperly.
Set the server up for replication, create a publication in the DB in question. Publish any table (not important which one) and then completely remove replication again.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability