Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 32419

Introducing new GCN Kafka broker and web site for transient alerts,
2022-07-20T21:07:26Z (2 years ago)
Judith Racusin at GSFC <>
Scott Barthelmy (GSFC), Eric Burns (LSU), Dakota Dutko (GSFC),
Meredith Gibb (GSFC), Victor Gonzalez-Leon (GSFC), Tess Jaffe
(GSFC), Ryan Lorek (GSFC/UMBC), Israel Martinez (GSFC/UMD), Tom
McGlynn (GSFC), Judy Racusin (GSFC), David Simpson (GSFC), Leo
Singer (GSFC), Teresa Sheets (GSFC), Alan Smale (GSFC), and
Dongguen Tak (DESY) report on behalf of GCN, TACH, and HEASARC:

We are pleased to introduce the new General Coordinates Network,
the evolution of the Gamma-ray Coordinates Network (now referred
to as GCN Classic) using modern, open-source, reliable, and secure
alert distribution technologies that have been established by the
broader astronomy community and promoted by the Vera C. Rubin

We invite you to join one of our three public Zoom webinars for an
overview of the new GCN:

August 1, 2022 12:00-13:00 UTC (best for Atlantic):

August 1, 2022 20:00-21:00 UTC (best for Pacific):

August 2, 2022 04:00-05:00 UTC (best for Asia and Oceania):

GCN has a redesigned website, and a new
improved method of streaming GCN Notices called GCN Classic over
Kafka. All three classic GCN Notice formats (text, VOEvent,
160-byte binary packet) are now also available over Kafka. This
new Kafka streaming service can be used as a drop-in replacement
for GCN Classic socket and VOEvent subscribers, with an upcoming
release serving email subscribers.

GCN Classic over Kafka has the following advantages over the
legacy delivery methods:

- Self Service: Users can manage their own accounts and
  subscription settings through the new GCN web site,
- Open Standards: Notices are sent using one standard protocol,
  Apache Kafka.
- Open Source: Receive GCN Notices using open-source client
- Highly Available: Notices are served by a cluster of redundant
  Kafka brokers in the cloud.
- Secure: Notices are protected in transit with SSL/TLS.

The old GCN Classic web site,, and the
legacy socket delivery methods will continue to be supported for
the foreseeable future. However, starting later this year new
features and notice types will only be available on the new web
site and GCN Kafka, including:

- Self-service configuration of GCN Notice notifications over email
- Modernization and enhancement of GCN Circulars
- Unified, searchable GCN Notice and Circular archive integrating
  the features of the GCN Viewer
  (, GCN Circular 31036)

For questions, issues, or bug reports, please contact us via:

HEASARC feedback form:

GitHub issue tracker:

[CORRECTION: de-mangled links that were processed through Microsoft
Outlook's Safe Links]
Looking for U.S. government information and services? Visit