GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide.

Circulars allow the GRB community to email messages to a central queue where they are automatically vetted and distributed to the entire GRB community. These prose-style messages allow the community to coordinate and make optimum use of its limited resources.


  1. Email your submission to gcncirc@capella2.gsfc.nasa.gov.

  2. The email subject line must contain at least one of the strings in the list of instruments and source types.


To receive or submit to this GCN Circular list, you must first be added to the vetted list. The purpose is to prevent spam and other unwanted messages. Incoming emails from an address that is not part of the list will be rejected.

You can request access through the sign up page. There are no restrictions to being added to the list. It is recommended that you send an email to Scott Barthelmy who will confirm that your account name and domain are correct.

Submission process

To submit a GCN Circular send an email to gcncirc@capella2.gsfc.nasa.gov. It is recommended that you copy Scott Barthelmy.

Please follow the style guidelines. In particular, the email subject must contain at least one of the following case-sensitive strings:

A copy of the body of your email will be distributed along with the following header:

NUMBER:  <serial number>
SUBJECT: <exact copy of your email subject>
DATE:    <date and time>
FROM:    <the name and email you used to register>

We will verify that you are a valid submitter. Make sure you are submitting your email from the address you used to sign up.

You will receive either a success or a problem report:


GCN Circulars are atuomatically archived. There are various ways to access past Circulars: