Final answer:
The unit called upon for responding to computer security incidents after being notified and tasked with the situation is the Computer Security Incident Response Team or CSIRT.
Step-by-step explanation:
When a technician detects and reports an incident that requires a coordinated response, the unit that is notified and tasked with acting as first responders is known as a Computer Security Incident Response Team or CSIRT. This team takes charge of the situation and formulates an appropriate response to manage and mitigate the effects of the security incident.