Hanging together? -- The future of the CMB in the UK

[Warning: this post will be fairly technical and political and may only be of interest to those in the field.]

I spent the first couple of days this week stuck in a room in Cambridge with about 40 of my colleagues pondering a very important question: what is the future of the study of the Cosmic Microwave Background in the UK?

Organized by Keith Grainge of Cambridge’s MRAO, and held at Cambridge’s new Kavli Institute for Cosmology, the workshop brought together a significant fraction of the UK CMB community, from Cambridge itself, Cardiff, Imperial, Manchester, Oxford and elsewhere.

With the recent cancellation of the Clover experiment by STFC, there is no major UK-led CMB experiment (I am making a distinction between CMB experiments per se and those with other primary purposes, such observing the Sunyaev-Zel’dovich effect with AMI, or astrophysical foregrounds with QUIJOTE.) However, there is a huge amount of CMB expertise in the UK, from the design of detectors and telescopes through to the analysis of CMB data.

In the short term, it seems there is some appetite for attempting to revive the Clover effort at some level, perhaps in collaboration with other experimental teams outside of the UK. The major driver — and the only way it makes any sense at all — is to get this done quickly, before the other experiments pursuing the same goals begin to gather data (in the interests of full disclosure, I should point out that I am involved in a couple of those other experiments: EBEX and PolarBear). This decision, I imagine, will be dominated by the politics and economics of the current STFC funding debacle fiasco debate as well as what I understand are the internal relationships of the Clover team.

So of more scientific interest is the question of what to do next. Right now, the UK astronomy and particle physics community is undertaking a series of consultations to figure out what it thinks are the most important topics, instruments and experiments to concentrate upon over the next few years. One very real possibility is that we could decide not to lead any new CMB experiments, but just to continue to lend our expertise to other efforts. This is cost-effective but unsatisfying, especially to experimentalists who want to take the lead in the design of new efforts. The only viable alternative, I think, is for the community to come together and, with apologies for the cliche, speak with a unified voice in support of a coherent plan. There is enough expertise in the UK to produce great CMB science over the next decade, but it is thinly spread. The basic design of any such experiment is clear: thousands of detectors observing the sky over as many frequencies as possible. But the details — exactly what sorts of detectors, flown from a balloon or stationary on the ground, or to wait for a future satellite — will be crucial to the success or otherwise of the experiment. Unfortunately, these decisions can often degenerate into “not-invented-here” syndrome and personality clashes between strong scientific egos. But as Ben Franklin said on signing the Declaration of Independence, “we must, indeed, all hang together, or assuredly we shall all hang separately.”