Skyalert is broader than astronomy, and works with rather general concepts, as described below.

Sensors: Some sensors report events directly, others make continuous data streams. In the latter case, there may be a pattern-matching pipeline, to decide when there is something “interesting” in the data. But in both cases, a sensor produces “observation events”: time-stamped bundle of data that expresses what the sensor is reporting.

Events: We perceive the notion of “event” in several ways: as discussed above, it can be the output of a pattern-matching algorithm on a continuous stream from a sensor. Other types of events signal the change in status of a sensor: online, offline, in lock, etc. There are also follow-up events, where a sensor is directed to point at what another sensor has reported in an observation event.

Action: Events may cause action. Such actions may include fetching from an archive, running a computation, directing a follow-up sensor, or alerting a human. Such actions are taken predicated on a trigger function, that examines all the data associated with the original observation, including archives and follow-ups, and produces a boolean result: to take the associated action or not.

Portfolio: All the data about the event is stored together in a “portfolio”. It is multiple sourced because different sensors, archives, mining software, follow-up sensors, etc are all built by different organizations and report different kinds of data; so it can be difficult to assess the meaning of a portfolio for decisions. We solve this by taking a very simple approach, where everything in the portfolio is a key-value pair, with complex data objects having both a URL pointer as the value, and a semantic URI defining the nature of that complex data. The meanings of the key-value pairs are provided well in advance of the event cascade by those who are providing events. Note that actions may result in new follow-up events being added to the portfolio, which may result in further actions.

Skyalert.org collects many streams of astronomical events, and provides the capabilities described above for real-time intelligent filtering and actions. Microsoft Worldwide Telescope provides display of all recent events, and allows detailed examination of individual events in many wavelengths. Skyalert also allows users to build custom event feeds (Atom), create custom software modules for mining the portfolio, and get custom messaging when interesting events occur. In terms of astronomical transients, we are working closely with the LSST project, expected to produce 100,000 astronomical events per night. We are working with the LIGO/Virgo gravitational wave detectors, as both producers and consumers of events. We have relationships with many event providers, including CRTS, SWIFT, Fermi, GALEX, LOFAR, VERITAS, MOA, and many others.

We are interested in working with people who might be interested in:

• Adapting the above model to other fields outside astronomy,
• Scalable real-time networking for the LSST firehose of events,
• Pushing the envelope with feeds, instant messaging, and distributed repositories.
• Working with Worldwide Telescope to display event histories and correlations.

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