Introduction

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.

Bob Mann

Call for Phase C DEV Work Packages

UK Contributions to DESC Operations

For LSST:UK

Mike’s galaxy classifying machine has been put to other uses recently. Having learned through collaboration with citizen scientists to classify galaxies, it can be repurposed as a similarity search - give it one galaxy, and it will return those it thinks are similar. (You can try it for yourself at bit.ly/decals_similarity). This mode of working, where a researcher or a citizen scientist who has found something unusual can immediately search the data for other examples, illustrates a different form of human-machine collaboration likely to be useful in the Rubin era. It’s something already used to great effect by the Gravity Spy team, who have a dedicated team of citizen scientists sorting through and classifying sources of noise in the hyper-sensitive LIGO and VIRGO data. What works for gravitational waves may be useful for exploring the panoply of astrophysical sources hidden in the Rubin Observatory data.work package 3.10 Joe Zuntz and James Perry are supporting the operations of DESC, the Dark Energy Science Collaboration. This is primarily software development, contributing to the pipelines that will run the cosmology analysis of Rubin data, and to the simulation tools that will stress-test the process.  Our recent deliverables have covered both these areas.

On the simulation side, James has recently completed contributions to GalSim  the galaxy image simulation library that is in wide use in the collaboration, and beyond. Developed as part of the Great 3 cosmic shear challenge, GalSim is one of the few codes with sufficient rendering accuracy for weak lensing analysis. James has added GalSim features to better model pixel boundaries on the telescope focal plane - the Brighter-Fatter effect means that the effective size of pixels are non-uniform in any given image, and these features given the library enough flexibility to model this at LSST accuracy.

On the analysis side, Joe has recently completed a deliverable that brings photometric redshifts into the primary DESC lensing and clustering pipeline. DESC will analyze what has come to be called "3x2pt": the combination of correlation functions in lensing with those in clustering. This analysis needs high quality (and, more importantly, well-characterised) photometric redshifts (PZs), which in DESC are generated via the RAIL package, which wraps a collection of community PZ codes. Joe has added modules to TXPipe, the DESC pipeline code, that link it to RAIL, completing a key step in the pipeline.

Joe Zuntz

Appointment of the LSST:UK Education and Public Outreach Coordinator

Alastair Edge and Bob Mann

Forthcoming meetings of interest

Several meetings of potential interest have been scheduled for the coming months. As well as the winter DESC sprint week (in week beginning 25th October), the Rubin Observatory has announced an LSST Survey Strategy Workshop during 16th–17th November (which will be held online). More details are expected in the coming weeks via the DESC Confluence site and the Rubin Observatory Community Forum, respectively.

Note that the current list of forthcoming meeting 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

George Beckett

Announcements

If you have significant announcements that are directly relevant to LSST:UK and would like to share the announcement in a future newsletter, please contact the LSST:UK project managers.