Resurrection (The Monster)

A. E. van Vogt's "Resurrection" aka "The Monster"

"An extremely positive doomsday story. It's even humorous - occasionally." -- Variety SF

Nasty aliens attempting colonization of a dead earth get a rude shock.

Long in future, with far more technologically advanced humans, one fine day all animal life on earth dies. Cause was a nucleonic storm. It swept in from outer space. It brushed this edge of our galaxy. It was about ninety light-years in diameter, beyond the farthest limits of our power. There was no escape from it. We had dispensed with spaceships, and had no time to construct any. Castor, the only star with planets ever discovered by us, was also in the path of the storm."

An unspecified thousands of years later, aliens called Ganae (from planet Gana) land on earth. These are very violent ruthless creatures - they've been stripping whole planets of life so they can overtake those worlds. Earth is perfectly habitable for them.

And the visitors are suspecting it's their kind that has been behind earthlife's demise - but aren't sure. Since all animal life is dead, they want to find out the cause of mass deaths before proceeding with their own colonization of it.