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There will be a network outage, Sunday, April 26 from 13:00 EDT - Monday April 27 01:00 EDT. All services, web sites, and systems that require access to the internet will be affected by this work.


GCN: The Gamma-ray Coordinates Network (TAN: Transient Astronomy Network)

This Sunday (26 Apr 15) from 18 to 06 UT (Monday, 27 Apr 15) GCN internet access will be down
for a few intervals while there is a NASA-wide (all Centers) upgrade of the major routers.
There will be a 1-2 hour outage interval near the beginning of the 12-hr total window,
and there will be a few 3-5 minute outages spread across the rest of the total window.
During each of these outages, there will be no socket connections and no email distribution capbilities.
(This was announced to happen last weekend, but it did not.

The GCN system distributes:
  1. Locations of GRBs and other Transients (the Notices) detected by spacecraft (most in real-time while the burst is still bursting and others are that delayed due to telemetry down-link delays).
  2. Reports of follow-up observations (the Circulars and the Reports) made by ground-based and space-based optical, radio, x-ray, TeV, and other particle observers.
These two functions provide a one-stop shopping network for follow-up sites and GRB and transient researchers.

The GCN system can be explored using the links above and below.

Invitation to subscribe to the GCN/TAN here.

System Status
System Status: Latest update: 27 Feb 2015 (UT)
What's New
What's New: Latest update: 30 Apr 2014 (UT)

thumbnail of GCN physical network
The physical GCN network. (Click to enlarge.)

Latest Gamma-Ray Bursts

GCN Circulars Archive
GCN Reports Archive

The GCN/TAN contact is: Scott Barthelmy,, (301)-286-3106,

A service of the Astrophysics Science Division (ASD) at NASA's GSFC

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    This file was last modified on Thursday, 23-Apr-2015 11:10:00 EDT