What is GCN?

The General Coordinates Network (GCN) is a public collaboration platform run by NASA for the astronomy research community to share alerts and rapid communications about high-energy, multimessenger, and transient phenomena. GCN is the established platform for publishing discoveries and follow-up of gamma-ray bursts (GRBs), gravitational-wave (GW) compact binary mergers, and high-energy neutrinos. GCN distributes alerts between space- and ground-based observatories, physics experiments, and thousands of astronomers around the world.

The General Coordinates Network is the modern evolution of the Gamma-ray Coordinates Network (now referred to as GCN Classic, and formerly known as BACODINE/TAN), updated to use modern, open-source, reliable, and secure alert distribution technologies that have been established by the broader astronomy community.

GCN has two kinds of data products:

  • Notices are automated, machine-to-machine, generally real-time, notifications of detections and localizations of astronomical transients detected by space- and ground-based observatories.
  • Circulars are human-readable, citable, rapid but generally not real-time, bulletins observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans.

Client Configuration

To begin receiving GCN notices via Kafka, users have two options for setting up their listeners. The Client Configuration section describes how to connect to Kafka using Python or JavaScript. Once the listener is set up, users can specify which Kafka topics they wish to follow for different GCN notice types.


The GCN web site is an open source project built in Remix, a full stack web framework. Have an idea to make GCN better and want to contribute, or have a bug to report? Head over to our contributing documentation for our quick start instructions.


Check out our roadmap for features that are under development, including the Unified Schema and the GRB Name Server.