Commander Aegir, of the Asgard ship Valhalla, was contacted by Thor when the Asgard colony of Orilla faced annihilation by Replicators. Aegir and his fleet of approximately six Asgard ships fired upon Fifth's Replicator ship as it exited hyperspace above the planet. The Replicator ship was destroyed, however debris rained down upon the planet and continued to infest the colony until Thor and SG-1 developed a disruptor weapon capable of defeating the Replicators.
Cross Reference: Asgard, Orilla, Penegal, Replicators, Thor
Episode Reference: New Order