mass-effect-3
When I'm viewing the Galaxy Map form the Normandy and selecting where to go with a mass relay, some of the systems appear to pulse or blink.
At first I thought this was to indicate mission locations, but some of them are blinking with no obvious missions to complete. It's clearly not the presence of the Reapers.
Why are some of the systems blinking?
Galaxy-at-War is Mass Effect 3's multiplayer. That's not the important bit - what you should be interested in instead is the "Galactic Readiness Rating". The idea is that the Reapers are invading, and the Galaxy is not, well, ready. How the main storyline resolves depends on the Galactic Readiness Rating when you go on the final mission.
There are three ways to increase Galactic Readiness Rating:
Here is where you can find more details on how to increase readiness. Additionally, the Mass Effect Wikia has a little more on it.
That screen represents all aspects of Galactic Readiness, and will default to 50% for all Mass Effect 3 players.
The Krogan DMZ is directly below the Serpent Nebula (which houses The Citadel).
Best Answer
Blinking indicates that you currently have an active mission in your log to complete there.
If you see no obvious mission, scan around the system and you should find a war asset or fuel depot to recover.