UK CMB Town Hall Meeting

We invite all members of the UK CMB and cosmology communities to an open “town hall” meeting in order to discuss the current status of observational CMB studies, the emerging plans for future experiments, and the role of the UK community in these future plans. A number of recent developments in the field motivate the organisation of this meeting now. In particular, several UK groups have recently joined the Simons Observatory and a number of dedicated satellite missions are currently under discussion. These include the Japanese-led LiteBIRD satellite, which ESA is considering participating in as a "Mission of Opportunity” if it is selected by JAXA, and a possible bilateral Indo-European implementation of the CORE mission concept that was recently proposed to ESA. Moreover, plans for the $400M+ ground-based Stage-4 CMB experiment, “CMB-S4” are gathering apace. This project is mostly being driven by US groups at the current time. At the same time, the European community is considering what its role should be in the future of this area. In terms of ground-based and balloon-borne experiments, the European CMB Coordinators group (which includes UK reps Brown & Challinor) is planning a White Paper setting out the priorities in terms of both the science questions and the experimental facilities that the European CMB community would like to pursue. In order to feed into this White Paper, we would like to use this meeting to solicit the opinion of the UK community on the following top-level questions:

• What, if any, contribution should Europe be making to existing S3/S4 plans?
• Do we need Northern coverage and if so, how do we address it?
• To what extent do we extend frequency coverage on both the low and high ends of the spectrum and if so, how far?
• Do we need spectral distortion measures and if so, what is the process?

Note that you can provide your answers to the above ECMB questions ahead of the meeting using this form.

The meeting will take the form of a small number of scene-setting talks in the morning with the afternoon dedicated to discussion sessions covering both satellite and sub-orbital areas.

* With many thanks to the Cosmoparticle Initiative at UCL for sponsoring the meeting coffee breaks.