LSST:UK newsletter 57 (July 2025)
- 1 Introduction
- 2 LSST:UK in focus at NAM2025
- 3 Junior Associates Network at NAM2025
- 4 Lasair-LSST for users of Lasair-ZTF
- 5 LSST AGN Science Collaboration Annual Meeting
- 6 Rubin Data Academy 2025 and Data Preview 1
- 7 European Astronomy Society Annual Meeting
- 8 Fantasy Football League – sign-up open
- 9 Recent LSST:UK Science Centre outputs
- 10 Forthcoming meetings of interest
Introduction
Commissioning observations continue, although with some interruptions due to the bad weather, with attention turning to the performance of the Science Validation surveys, driven by the Feature-Based Scheduler, in which mode >750 science visits have been taken in a single night, comparable to what will be required during survey operations.
The end of June and the start of July saw the 2025 Rubin Data Academy, in which the Rubin Community Science Team presented a series of sessions (recordings of which are now available, see below) intended to develop familiarity with Data Preview 1 and the tools within the Rubin Science Platform that can be used for its analysis by introducing the impressive range of tutorials that have been released with DP1. Those who reach the point of doing science with DP1 data should note that Rubin has a webpage detailing how to cite LSST data and services, as well as standard acknowledgement text.
The image on the right shows a screenshot from Orbitviewer, a new app that will provide visualisations of the vast numbers of solar system objects to be discovered by the LSST, using orbital data from the Minor Planet Center.
This is, of course, prime conference season, and this newsletter includes reports of LSST-related sessions at the EAS Annual Meeting in Cork and the National Astronomy Meeting at Durham, as well as the LSST AGN Science Collaboration Annual Meeting.
Presentation materials from our NAM sessions are available online, while I would particularly like to highlight the report below of the lunchtime session held at NAM to discuss our proposed new Junior Associates network: the session itself was very successful, attracting many participants new to LSST:UK and capturing lots of ideas for what the network should do, while the report includes a link for those wishing to help set it up over the next few months, ahead of a planned launch in the autumn. Watch this space!
@Bob Mann
LSST:UK in focus at NAM2025
From 7-11 July, Durham University hosted the National Astronomy Meeting 2025, bringing together astronomers, space scientists, and educators for a week of scientific exchange and cross-disciplinary collaboration. With its theme of community, NAM2025 highlighted how astronomy not only connects researchers across institutions but also engages wider society through outreach, education, heritage, industry, and the arts.
The programme featured a rich mix of plenary talks, parallel science sessions, workshops, and public engagement activities. A strong presence from early career researchers (ECRs) added momentum and fresh perspective throughout the week.
LSST:UK featured prominently during the first two days, with two parallel sessions and a lunchtime discussion reflecting the UK community’s growing engagement with the Rubin Observatory and preparations for early science. While the sessions touched on the upcoming release of the first on-sky data from the LSSTCam and the earlier ComCam observations, the focus was broader – emphasising practical pathways for UK researchers to get involved, build readiness, and contribute to early Rubin science across a wide range of topics.
Topics included overviews of LSST:UK and the international science collaborations, tutorials on accessing and working with Rubin data, and updates on technical readiness across the UK network. Alongside scientific presentations, the sessions featured interactive training, live demos, and Q&A tailored to early career researchers, offering clear pathways for newcomers entering Rubin science.
Together, these sessions showcased not only the technical progress but also the collaborative ethos driving LSST:UK forward. As the community prepares for Data Preview 1, the momentum built at NAM2025 marks a strong step toward impactful early science.LSST LSST:UK parallel sessions
Session 1
Vera C. Rubin Observatory and the Legacy Survey of Space and Time (Federica Bianco)
Introduction to LSST:UK and UK involvement in Rubin/LSST (@Bob Mann )
Introduction to early science with Rubin/LSST (@Graham Smith )
Lasair: the UK Broker for Rubin Alerts (@Roy Williams )
The ComCam Campaign and Data Preview 1 ( @James Mullaney)
Session 2
The LSST-NIR Fusion Pipeline: Advancing Multiwavelength Astronomy with Rubin LSST and VISTA (@Elham Saremi )
The LSST AGN Science Collaboration and Its Early Science Plans (Niel Brandt)
Dark matter science with Rubin LSST: weak lensing and stellar streams (Keir Rogers)
Galaxy-Halo Connection Across Cosmic Time: Preparing for LSST with Deep Survey Fields (Natalia Stylianou)
Enhance LSST Cosmological Constraints Using Data-Augmented Redshift Calibration and Variational-AutoEncoder Marginalisation (@Yunhao Zhang )
The Effects of Template Generation in Year 1 of LSST (@James Robinson )
Forecasting Cosmological Constraints from LSST Strong Lenses: A Multi-Probe Hierarchical Approach (Tian Li)
Propagating photometric redshift uncertainties for LSST and Stage-IV surveys (@Jaime Ruiz Zapatero )
LSST / LSST:UK for Early Career Researchers
Introduction and overview (@Matthew Temple )
Junior DESC Organisation (JuDO) (@Thomas Cornish)
Structured discussion of scope and organisation of Junior Associates network (led by Steve Ardern)
Access the presentations here: https://lsst-uk.atlassian.net/wiki/x/AoCT_w
@Elham Saremi
Below: Engagement activities took place over the week
Credit: Durham University
Junior Associates Network at NAM2025
July saw the return of the RAS National Astronomy Meeting (NAM) to Durham University for the first time since the very first NAM back in 1992. Back then, it had an attendance of about 300. Now, 33 years later, and with nearly 1000 in-person attendees, this conference was a great opportunity to meet and network with fellow early career researchers (ECRs) looking to make use of the new LSST data.
To facilitate this we held a lunchtime session, chaired by Andrew Wilson, to introduce the LSST:UK Junior Associates Network, which is being created to support ECRs in getting the most out of LSST.
Matthew Temple, co-chair of the LSST AGN Science Collaboration, kicked off the session by providing an overview of the LSST survey and the LSST:UK consortium. This was followed by Tom Cornish, who told us about JuDO, an ECR network in the Dark Energy Science Collaboration, that gave an overview of how a current ECR network can work effectively.
To engage with ECRs and find out what they would like from the network, Steve Arden and Clara Pennock led an interactive session. They solicited ideas on the topics of what ECRs need, what the network could offer, how the network should be structured, and how we should communicate with each other. One of the main takeaways from this was that ECRs wanted tutorials/guidance on how to make the best use of the incoming vast amounts of LSST data. Another common thread was making it easy to interact and ask for advice. For example online meetings, events at conferences, and a system for online communication.
We will be reviewing the feedback gained during the session over the coming weeks in preparation for the network to launch at the start of the new academic year.
If you would like to become involved in helping to set up the Junior Associates Network, register your interest by completing the form: https://forms.gle/XgnogZ3XxwZM3Eh49
All of the NAM LSST:UK presentations, including the lunchtime session and the feedback are available at: https://lsst-uk.atlassian.net/wiki/spaces/HOME/pages/4220747778
Steve Ardern, Astha Astha, @Thomas Cornish, Dimple, @Garreth Martin , Clara Pennock, @Matthew Temple, @Andrew Wilson
Lasair-LSST for users of Lasair-ZTF
The Lasair project has two websites: http://lasair-ztf.lsst.ac.uk for ZTF, and http://lasair-lsst.lsst.ac.uk for the Rubin-LSST alerts. There is also a web address http://lasair.lsst.ac.uk that currently redirects to ZTF and soon will redirect to LSST.
We note that lasair-ztf will continue operating. The ZTF survey has been running since 2018, and from the beginning has used similar technology to the Rubin alert stream – public alerts with Kafka transport and AVRO messages – and has therefore been a very useful as a prototype to Rubin alerts.
Lasair concepts retained
The basic concepts are the same between ZTF and LSST:
filtering using attributes tied together with SQL, as well as geometric criteria
‘active’ filters so that results are immediately transmitted via email or kafka
intelligent crossmatch from Sherlock
watchlists and watchmaps; when "active" there is real-time matching
annotation by users and other brokers to add to the information portfolio aboout an object
a REST API and a python client
Key differences
The LSST survey will produce about 30 times as many alerts as ZTF, up to 10,000,000 per night
LSST is six bands (ugrizy) and the public ZTF is two bands (gr). In the latter case it is reasonable to compute features for g and r separately, and the filter would have criteria that can be satisfied by a feature either the g or the r lightcurve. But with six bands, we have used the two-dimensional wavelength-time surface rather than six separate one-dimensional lightcurves.
Difference Flux replaces Difference Magnitude. The flux of a source is clearly positive, and it is reasonable to take the logarithm to get magnitude. But the difference in flux between two times can be positive or negative, and ZTF used an awkward scheme with the logarithm of the absolute value of the flux difference, together with a sign bit. The LSST alerts are simply difference flux in nanoJanskies: 10,000 nJ is magnitude 21.4 and 1,000,000 nJ is magnitude 16.4.
Pairs of detections. If a source is rapidly brightening, it is difficult to measure colour if detections in different bands are at different times. But the LSST cadence makes pairs of detections in different bands, separated by only 30 minutes, from which a reliable colour measure can be made.
New features for filters
Jump filter in two different bands: For each band, we take the mean and variance of flux between 70 days and 10 days in the past, then compute the number of standard deviations (sigma) the current flux is from that baseline. The quantity "jump1" is the largest of those, and "jump2" is second largest, from another band.
Extinction correction: Lasair computes the interstellar dust reddening/extinction corresponding to the sky position of an object, using the Schlegel, Finkbeiner & Davis (SFD) dustmap, and the E(B-V) is reported as. the attribute
ebv.BazinBlackbody, a 2D temporal spectro parametric fit: Each point of the panchromatic lightcurve is considered to be a flux at given time and wavelength; we try to fit two models and take the best. Each model has a blackbody spectrum in wavelength, and the time part of the model is either exponentional flux (linear rise in magnitude) or Bazin flux, with a rise rate then a fall rate. The fit is made with extinction-corrected flux values.
Temperature: For ZTF, it is reasonable to use a colour index (magnitude difference) for example "g-r" for the colour of a source, but the paired observations that LSST makes could be any of u+g, u+r, g+r, r+i, i+z, z+y, making it very difficult to understand a colour index. Therefore Lasair makes a blackbody fit to the two fluxes in two bands, and reports an effective temperature. The fit is made with extinction-corrected flux values.
Absolute magnitude, extinction corrected: If the Sherlock system reports a host galaxy for the object (SN or NT classification), and the redshift of that galaxy is known, then Lasair computes an extinction-corrected absolute magnitude for the object.
Website improvements
Community resources: While any filter, watchlist, or watchmap can be public, some are emphasised and listed as "community resources", which you can see by clicking the ‘Resources’ in the left margin of lasair-lsst. One looks for flux jumps in white dwarfs, another finds supernova-like light curves with a host galaxy. There is a watchlist of Abell clusters and RR Lyrae; there is a watchmap of galaxies within 5 Mpc and 50 Mpc.
More comprehensive documentation: The improved documentation includes a cookbook, new videos, how Lasair is different from other brokers, the API client, and other topics.
Example Notebooks: These illustrate the use of the API for SQL queries and cone search, for fetching the kafka stream from and active filter, and the implementation of the new lightcurve features described above.
Multimessenger support: Lasair is now ready to search for the optical counterpart of a graviational-wave event, by sorting LSST alerts by likelihood. If an object has a host galaxy with distance, then the 3D gravitational-wave skymap is used for priority, otherwise the 2D skymap is used.
Follow the Lasair blog
The best way to keep up to date with Lasair is to follow the new dedicated Lasair blog on the LSST Community Forum. Watch the category (click on the bell icon and select ‘Watching') to receive notifications whenever the Lasair team post new technical and science updates. As an interactive blog, users can also request support and post bugs so that the Lasair team can follow up and resolve any issues.
@Roy Williams
LSST AGN Science Collaboration Annual Meeting
Since 2022, the LSST AGN Science Collaboration has organised an annual meeting every July. With support from LSST:UK and the Royal Astronomical Society, Durham University hosted a hybrid workshop from 14-17 July 2025 with the dual aims of (i) bringing together existing members of the AGN SC, and (ii) engaging members of the wider UK AGN community who are interested in learning more about Rubin/LSST.
In total we had 44 in-person and 33 remote attendees, with 16 in-person and 4 remote attendees coming from LSST:UK institutions, and the rest from across Europe, Asia, South and North America. Over the past year the UK has regained its second-place rank in terms of number of AGN SC members (overtaking Italy, but a way behind the US), and this meeting was a timely opportunity to highlight UK leadership in Rubin/LSST projects with key contributions from @James Mullaney (Sheffield) demonstrating the Rubin Science Platform and DP1 ComCam data, and @Elham Saremi (Southampton) describing the joint Rubin-VISTA pipeline processing which is part of the UK's in-kind contribution to Rubin.
The meeting was structured with a mix of contributed science talks and parallel breakout sessions including tutorials, hackathons with the new DP1 data, and discussions planning for future science with both DP2/DR1 and the first nightly alerts. All sessions were live-streamed on zoom, thankfully without any major technical problems, and recordings of the talks have been posted to YouTube. One attendee remarked that “The hybrid format was so smooth that being remote almost felt the same as being there in person, also during discussion and Q&A!”
@Matthew Temple
Rubin Data Academy 2025 and Data Preview 1
Aiming to get attendees familiar with the Rubin Science Platform (RSP) and with the contents of Data Preview 1 (DP1), the 2025 Rubin Data Academy took place from 30 June-3 July, with each of the ten sessions run at least twice, at different times, to suit attendees located around the world.
The course was delivered by members of the Rubin Community Science Team (CST), who also offered a series of drop-in sessions during the week; during these sessions attendees could ask for help with specific problems they had encountered working with DP1 data using the RSP.
Links to the course materials – slide sets and a recording of each session – are available from a Rubin GitHub repository and have great lasting value beyond the course itself. For the most part, the sessions comprised walk-throughs of some of the vastly-expanded set of tutorials provided by the CST for use with DP1. Extensive sets of tutorials exist for both the Notebook and Portal Aspects of the RSP – although some of the Portal tutorials are ‘Coming Soon’ – while a single tutorial shows how the API Aspect can provide access to DP1 data with an existing third-party tool (TOPCAT).
The tutorials come in three levels:
100-level tutorials provide basic tours of the RSP, with each focusing on the use of a single piece of RSP functionality or tool - e.g., Notebook Tutorial 103.1 shows how to use the data butler to access image data within a Jupyter notebook;
200-level tutorials each illustrate the different types of Rubin data product and how to work with them - e.g., Notebook Tutorial 201.1 looks at the attributes stored in the Object catalogue and how it can be accessed from within a notebook; and
300-level tutorials execute end-to-end scientific workflows using DP1 data - e.g., Notebook Tutorial 304.2 identifies, and studies the properties of, red sequence galaxies in the cluster Abell 360.
Taken together, the tutorials provide all the basic information needed for someone new to LSST data and the RSP to work out how what data products they would require for a particular science analysis and how to implement it within the RSP, while the Data Academy videos provide (especially if viewed at 1.5x speed) an efficient overview of what the tutorials contain and how to navigate a path through them appropriate for your level of existing knowledge and your goals for DP1.
@Bob Mann
European Astronomy Society Annual Meeting
The 2025 meeting of the European Astronomy Society took place in Cork, Ireland, from June 23-27 and included a special session entitled The Vera C. Rubin Observatory Legacy Survey of Space and Time: a European pathway from First Look to data flows.
The goal of the session was to bring together astronomers who are already involved with LSST (for example through in-kind contributions to Rubin), while at the same time informing and engaging with the wider European community to encourage broader participation. With that in mind we planned a programme with three key goals: (i) educating the EAS community about the structure of the Rubin ecosystem; the roles of the Rubin Project, Discovery Alliance and the LSST Science Collaborations, (ii) presenting and discussing science opportunities with the public alert-stream data, and also early science with ComCam data, and (iii) doing Rubin-related science “together” including synergies with other European-led surveys.
The special session was held on Wednesday 25 June, and featured presentations from researchers at Southampton, Belfast and Oxford as well as the Lasair broker team, which gave good visibility to the ongoing work within the LSST:UK community.
With the date of the Rubin First Look event planned as Monday 23 June, we were very grateful to the EAS organisers for also finding us a room at short notice to allow us to host our own Watch Party in Cork. Beth Willman (LSST Discovery Alliance CEO) and Gautham Narayan (LSST SCs’ interim coordinator) were both attending EAS in person and gave personal insights to the history of the project and the data taken in commissioning, before the official unveiling was streamed from the US. It was standing room only (pictured above right), highlighting the broad interest in Rubin/LSST from astronomers across Europe.
@Matthew Temple
Fantasy Football League – sign-up open
Once again, our LSST:UK FPL league will open in game week 5 of the English Premier League – sign up and submit your squad by 19 September 2025.
After you have signed up and created your squad, you can then join our LSST:UK FPL league. The process to join our league involves a few clicks. Go to https://fantasy.premierleague.com/leagues and use the ‘'Create & Join New Leagues and Cups button followed by ‘Join a League & Cup’ then 'Join Invitational League & Cup’. Once there enter the code yh4n15 to join this year’s LSST:UK FPL league. If you are having any problems, signing up to the league, please let me know and I will try and guide you through it.
The late start to our league will give you all plenty of time to select your squad and come up with a witty name for your team, if you can make it astronomically related then even better e.g. last year’s ‘Chandra Saka Limit’. Note if you don’t have the time or inclination to pore over the lists of possible players to add to your team and stay within the £100M budget, you can instead use the auto-pick facility and it will do it for you.
Good luck!
Curious about joining the LSST:UK Fantasy Football League but don't know where to start?
Read the guide.
@Terry Sloan
Recent LSST:UK Science Centre outputs
The LSST:UK Science Centre has recently produced the following technical reports.
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D3.1.4 Zooniverse Classification Aggregation Tools | C. Lintott | Zooniverse-style citizen science projects, which involve multiple participants reviewing each subject (an image, light-curve or other display of data), necessarily include an aggregation stage where results from independent classifiers are combined to produce a consensus vote. The exact algorithm used will depend firstly on the type of task (e,g. selecting from a list of labels or marking a region on a light curve). For more difficult tasks, or projects in which the variance in performance between classifiers is large, more sophisticated algorithms may be used. While many project owners will wish to develop their own routines, we provide a library of simple aggregation tools for most project types. It had been assumed that users would want to run such aggregation locally. However, several long-running projects have reached the point where handling such large files is unwieldy. We therefore provide a batch aggregation service so users can obtain consensus results directly from the server, and if required pass these back to the Rubin Science Platform. | |
D2.5.1.2 Provision of hosting platform for Lasair Version 7 | G. Blow, M. Holliman, G. Beckett | A key responsibility of the UK DAC WP2.5 team is to provision and support the hosting platform for Lasair. This latest deliverable covers possible reconfigurations of the hosting platform for Lasair Version 7 (Oct’24—Mar’25). | |
D3.2.4 Implementation of LSST skymap and pipeline refactoring | E. Saremi | The objective of this deliverable was to enhance the NIR Fusion Pipeline for use with LSST commissioning data, particularly from ComCam. This involved ensuring compatibility with the latest LSST Science Pipelines release, updating the pipeline to version w2024.49, and incorporating significant improvements such as the integration of the new CalibrateImageTask for streamlined single-frame processing. A new skymap, "lsst_cells_v1," was generated specifically for ComCam data, representing a crucial step towards enabling comprehensive ComCam analysis. Furthermore, major updates were made to the obs_vista package, aligning it with LSST Science Pipelines v28.0.1 and optimizing parameters for near-infrared data processing. The second version of the obs_vista package has also been released. |
Forthcoming meetings of interest
Dates, locations and links… The current list of forthcoming meetings is always available on the Relevant Meetings page. You may also wish to check information held on the LSST organisation website LSST-organised events and the LSST Corporation website.
Dates | Meeting Title / Event | Meeting Website/ Contact | Meeting location / venue |
|---|---|---|---|
28/Jul/25 to 01/Aug/25 | Rubin Community Workshop | Marriott University Park, Tucson, AZ | |
15/Sep/25 to 19/Sep/25 | LSST@Europe7 | Poznań, Poland |
Members of the Consortium (not in receipt of travel funding through one of the Science Centre grants) may apply for travel support for meetings of this kind via the LSST:UK Pool Travel Fund. Details are available at Forthcoming LSST-related Meetings
If you have significant news or announcements that are directly relevant to LSST:UK and would like to share them in a future newsletter, contact @Eleanor O'Kane (email eokane@roe.ac.uk)
If you require this document in an alternative format, please contact the LSST:UK Project Managers lusc_pm@mlist.is.ed.ac.uk or phone +44 131 651 3577