National Aeronautics and
Space Administration

General
Coordinates
Network

NASA’s Next Generation Time-Domain and Multimessenger Alert System

A service of the Astrophysics Science Division at NASA’s Goddard Space Flight Center

https://gcn.nasa.gov

We invite you to join one of our three public Zoom webinars for an overview and tutorial on the new GCN.

Important: Follow one of these bit.ly links to register in advance and receive the actual Zoom meeting link.

August 1, 2022 12:00-13:00 UTC (best for Atlantic) https://bit.ly/3Pt2TH9

August 1, 2022 20:00-21:00 UTC (best for Pacific) https://bit.ly/3IT7Qqc

August 2, 2022 04:00-05:00 UTC (best for Asia and Oceania): https://bit.ly/3v2pNwV

Realtime Alerts Born of Necessity

GCN Enabled Seminal Breakthroughs in Astrophysics

There are two kinds of GCN data products:

The Changing Scientific Landscape

The Changing Technological Landscape

Introducing
the new GCN

Why switch to the new GCN?

	GCN Classic	GCN Classic over Kafka
Self-service	NO. Users need to contact administrator in order to make account and subscription changes	YES. Manage your own account and subscription settings through the web site
Open standards	NO. Notices are sent using three custom protocols	YES. Notices are sent using one standard protocol, Apache Kafka
Open source	NO. Custom software needed to receive notices	YES. Receive notices using open-source software
Highly available	NO. Notices are broadcast by a single server	YES. Notices are broadcast by a cluster of highly-available Kafka brokers in the cloud
Secure	NO. Notices are sent as plaintext	YES. Notices are protected with SSL/TLS

Streaming GCN
Notices in Python

## Install Python client

Run this command to install with [pip](https://pip.pypa.io/):

```
pip install gcn-kafka
```

or this command to install with with [conda](https://docs.conda.io/):

```
conda install -c conda-forge gcn-kafka
```

---

## Connect to Kafka

```python
from gcn_kafka import Consumer

consumer = Consumer(
  client_id='fill me in',
  client_secret='fill me in'
)
```

---

## Subscribe to topics and receive alerts

```python
consumer.subscribe([
    'gcn.classic.text.LVC_INITIAL',
    'gcn.classic.text.LVC_PRELIMINARY',
    'gcn.classic.text.LVC_RETRACTION',
    'gcn.classic.text.LVC_UPDATE'
])
while True:
    for message in consumer.consume():
        print(message.value())
```

---

# What’s next for GCN?

---

## We’re planning lots of enhancements in the near future:
* Self-service subscription to GCN Notice over email
* Modernization of GCN Circulars
  * Self-service subscription management
  * Self-service submitter registration using peer endorsement system
  * Correct handling of Unicode
  * Contextual parsing of links
  * Automatically minted DOIs and BiBTeX entries
  * Link ORCIDs to GCN Circulars
* Unified schema and alert format for GCN Kafka
* Integrated, searchable database of Notices and Circulars (GCN Viewer)
* Interoperability with other transient Kafka brokers (e.g. [SCiMMA](https://scimma.org))
* Alerts from new missions and facilities