Introduction
Rubin-LSST at NAM
Finally, a reminder that registration for the 2021 Project and Community Workshop (PCW) is open, with this year’s event taking place online from August 9-13 and featuring a wealth of programmatic, technical and scientific information related to the Rubin LSST.
Those with ideas for future newsletter items should contact the LSST:UK Project Managers (George Beckett and Terry Sloanlusc_pm@mlist.is.ed.ac.uk), while everyone is encouraged to subscribe to the Rubin Observatory Digest for more general news from the US observatory team.
UK contributions to Rubin commissioning: call for proposals
Colleagues are invited to submit proposals for value added contributions to Rubin commissioning. This opportunity follows acceptance of the commissioning element of the UK’s in-kind proposal, that was in turn based on the Expressions of Interest submitted by UK colleagues in 2020. It is therefore already agreed that the UK will contribute a summit team and a remote team. The focus of the former will include commissioning the wavefront sensor sub-systems, bringing expertise from VISTA. The latter will be a broader and larger team of colleagues contributing a wide range of scientific and operational expertise, much of which will concentrate on analysing commissioning data and giving feedback to the core commissioning team on the performance of the system. This is a great opportunity to get early hands on experience with Rubin data and science platform. Whilst there are strict rules around any scientific output from the commissioning period, experience gained with commissioning data will inevitably help with achieving early science. We are looking to agree the UK team with US colleagues by the end of 2021 with a view to UK team members getting started in early 2022. Travel and subsistence funding to support the UK team is already in place, and modest additional funding of commissioning effort is also available through this call. Full details of this opportunity are described in the call for proposals, which has a submission deadline of September 15, 2021. Please contact Graham Smith if you have any questions or would like to discuss proposal ideas in advance of submission.
The New World of Streaming Astronomical Data
Many of us are looking for a new home. Even if we are not, we all have a friend or family member who enjoys “property fantasy” – browsing the homes for sale and imagining themselves the buyer. We connect to a property broker, just as astronomers connect to an event broker: not just to find, but to have new results pushed to us, as soon as the property comes on the market (or as soon as the supernova explodes).
The “asking” way is to run the query every so often, and pick through the results to see what is new. There is also the “listening” way to get updates pushed to us: once a query is saved, simply check a box and you will get notified every time a suitable property comes on the market. Your query has been converted to a filter, that takes the stream of properties, and filters out the ones you want. In the screenshot shown here, it says “Create Alert” at top right, which causes an email whenever a property passes the filter.
You can (1) run your query and get all the results, consisting of both new properties and those you have already seen. Or (2) You can get notified whenever a new property comes up. Note that you only get new results, because the server remembers what it gave you before.
The Lasair event broker of LSST:UK has a “query builder” based on SQL syntax, with some extras: users can also query an intelligent crossmatch from catalogues, or upload a list of their favourite sources, or specify a sky area of interest.
In the past, an astronomer would query the database with their morning coffee, and try to find the new ones – method (1) above. Now however, the astronomer can check the “streaming” box on their saved query in Lasair. Alerts will be delivered as in method (2). While email is available for low-frequency streams, the “Kafka” protocol is more suitable for delivering alerts for further processing by machines.
The Kafka server remembers what has been delivered already, through the mechanism of the “groupID”. Each user-made query/filter generates a stream of alerts, that Kafka calls a “topic”. Having yesterday read from a topic with a given groupID, and then read today, you will get only the new alerts that have appeared on that topic since yesterday. You can run a program forever and continuously pull the stream, or you can start the program periodically, and in both cases each alert is received exactly once. Of course, you can get everything in the topic by simply choosing a new groupID, and it will start at the beginning of its cache – generally about a week’s worth of the stream. Details are available at the Lasair website -- see the last notebook at http://lasair-iris.roe.ac.uk/jupyter .
The streaming data has a link to the Lasair page corresponding to that object, showing the lightcurve and sky context, and links that give more information about the object, from the databases of the world. If you have a team, the alerts could be fed into a “marshal” -- so that different people can write comments and vote on whether telescopic follow-up is warranted. Or you could even have automated telescopic follow-up with no human in the loop.
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Recent LSST:UK outputs
LSST:UK has recently produced the following technical reports.
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Forthcoming meetings of interest
The schedule of events is relatively quiet over the Summer months, though we expect new workshops and meetings to be announced in the coming weeks. All are reminded that the 2021 Rubin Project and Community Workshop will take place online from 9th--13th August, although registration has now closed.