The future of UK Submillimetre Astronomy Workshop

Note, these are my personal observations and do not represent any official record and so should only be used as a basis for taking steps forward, or, generating further debate where it generates disagreement. I would like to thank all the speakers and the attendees for a highly productive workshop.

I will be asking the keynote speakers to provide a short summary of the key science drivers for submillimetre studies. These may well be used by the Director of the JCMT to provide input to the Science Board Panel looking at the future of the JCMT. The timescale for this is short as the Panel will report back to Science Board in April.

Regarding capability, there was, perhaps, a surprisingly common set of requirements from the galactic and extragalactic areas; namely:

• Unanimous agreement of the need to maintain the JCMT with SCUBA-2 and HARP for a further three years until 2016 – this is apparent from the recent SCUBA-2 survey resubmissions and the progress and science that are coming out of HARP. The science cases will follow as noted above.
• Overall, there was perceived to be a lack of need for a larger format or faster continuum camera (than SCUBA-2) unless there is an overwhelming cosmology driver, that was not apparent to those attending the workshop.
• Some alarm was displayed that ALMA upgrades are already being discussed without the overall community being aware of possibilities or how we can influence decisions – action on SPO to consider how to keep the community plugged in.
• In the longer-term (post 2020), SPICA was agreed to be a very high UK priority, not only for the science but also to become involved with the instrumentation to get the usual ‘lead-in’ to maximise science exploitation
• There was considerable interest in ALMA upgrades such as focal plane arrays on individual ALMA dishes.
• The extragalactic case needs a significant number of redshifts to be able to produce the science from the SCUBA-2 surveys – how to achieve this was one of the key questions and the conclusion was that this would not be attained by ALMA – so some other instrument would be needed.
• There seems to be a persuasive case for observing the C+ line from the submm galaxies – this would mean a spectrometer operating in the 450 window and preferably with a multi-object capability.
• The galactic science case would benefit from an immediate upgrading of HARP and ACSIS on the JCMT; most likely by an increase of the IF bandwidth to around 10GHz, giving a significant increase in the number of lines that could be observed simultaneously (e.g. to allow more tracers of regions of critical density). This needs an immediate small design study to be timely.
• For the larger heterodyne cameras available (e.g. SuperCam), would the developers be interested in bringing them to the JCMT either as guest instruments or even permanently
• Beyond this, what was apparent was that there was not obvious agreement on plans for the medium-term (i.e. beyond 2016) and this is the area where significant further work needs to focus as a matter of urgency.
• It was acknowledged that closing the JCMT would save around £2M per year and this could be used for future instrumentation in principle.
• There are a number of options of building new instruments for a facility instrument – like new multi-object spectrometers and which facilities to focus on (JCMT, APEX, CCAT, LMT) and at what wavelengths (350/450/850/1100).
• There was little enthusiasm for joining CCAT because of the perceived lack of further continuum survey requirement (by the time CCAT is operational), the possibility of using longer wavelengths to achieve the same ends (LMT), the uncertainty regarding spectroscopic capability and the timescale for CCAT
• Apart from the C+ studies, the case seems to be moving to either 850microns or into the LMT or longer ALMA bands for extragalactic and galactic science – this needs further teasing out.
• There is a need to invest in developing breakthrough technologies such as ‘spectrometers on a chip’ but these also need to be tied to specific science drivers in terms of an end-goal, rather than just technology for technologies sake.
• We need to have a ‘roadmap’ of what we need to get the science that we want – the near-term is agreed (retain the JCMT with SCUBA-2 and HARP) until 2016. The long-term is clearer with SPICA and ALMA upgrade options, we need to fill-in the medium-term options and possibilities thinking about the next step in the science roadmap – this is the key task leading into the Programmatic Review.

Additional input from Wayne Holland from the ‘galactic splinter session’

• Not everyone from the "community" was present although it is unlikely those absent would disagree with the conclusions reached (we think...);
• Certain science cases were not discussed (e.g. evolved stars), and hence need more time to address all areas;
• Not enough analysis has been done (or is available) in certain areas e.g. competitiveness of spectroscopic cameras (e.g. HARP v. HERA v. SuperCAM);
• ALMA is assumed to be going ahead as planned to full operation in perhaps 2015 (but see note below on upgrades);
• PDRA support is deemed to be crucial to exploit the new volume of data and maintain the UK's lead in many of the key submm projects/consortia.