A JCMT Update

Doug Johnstone, Associate Director JCMT

 

Brrr! I am writing this article from my old office at NRC-Herzberg in Victoria, and the weather outside is frightfully below zero. There is even snow on the ground. Quite the change from the balmy twenties that I have gotten used to in Hilo. It seems that after a full year as AD, I am finally acclimatising to life in the tropics.

 

In this update I will describe recent events at the JCMT, including progress within the JCMT Legacy Surveys, ann introduction to Semester 14A, and the present status of Extended Observing. A companion article on the ‘Continued Evolution of the JCMT’, by Gary Davis, Director of the JAC, details the on-going efforts to keep the JCMT fully functioning post-September 2014.

 

The JCMT Legacy Surveys (JLS) cover debris disks, star formation near and far within our Galaxy, nearby Galaxies, and cosmology. A colossal effort, the six individual component surveys combine for 3490 hours of science observation with SCUBA-2 (and almost 1000 hours with HARP). As of the start of November 2013, the JLS has reached almost 50% completion with SCUBA-2 (and 100% completion with HARP). Two important JLS papers have been published over the last six months: “First Results of the SONS Survey” (http://adsabs.harvard.edu/abs/2013MNRAS.435.1037P) and ``The SCUBA-2 Cosmology Survey: demographics of the 450 micron population” (http://adsabs.harvard.edu/abs/2013MNRAS.436..430R).

 

As mentioned in the 2013 Summer Solstice JCMT Update, completion of the JLS by September 2014 was likely to only reach around 70% without significant changes to both the telescope scheduling and observing practices. As such, the JCMT Board endorsed a 75:25 split in observing time between JLS and PI science for Semester 14A, up from the canonical 65:35 split for previous semesters. In making this change the continued importance of PI projects was recognized by the JCMT Board. Thus, the amount of time available for Canadian PI projects was preserved at about 100 hours during Semester 14A, with the semester running for 8 months from February 1st, 2014 to September 30th, 2014. I am pleased to report that, despite this being the last call under the present telescope arrangements, observers competitively requested this Canadian time, with an oversubscription rate of almost 2. The CanTAC and ITAC have met, discussed, and ranked all of these proposals and successful PIs should be receiving the good news soon. During Semester 13B many of the Canadian observers at the JCMT spent a few extra days visiting the JAC in Hilo, and in some cases presented eagerly anticipated science seminars. I look forward to more Canadian visits in 14A.

 

Extending JLS-time in Semester 14A will not entirely solve the under-completion issues within the JLS. Over the course of the summer, staff at the JAC have realized efficiencies in instrument set-up and calibrations, gaining almost half an hour of science observing on a typical night (that’s about a 5% gain in efficiency). Combined, these two enhancements to the JLS should allow the surveys to reach about 80% completion. Our goal, however, is even higher and the only way to accomplish this has been to introduce Extended Observing at the JCMT. To put this safely into effect the telescope and enclosure controls have been upgraded to allow operation from the JCMT Remote Operations Centre in Hilo. From October 1st onward, weather permitting, we have been adding up to two hours of JCMT science observations each day, operating the telescope remotely from Hilo from around 7:30am when the telescope operator and JCMT observer leave the summit until the day crew arrive at the telescope. At present these extended observations only take place from Monday-Thursday, when a day crew is headed to the summit. Experience has shown, however, that these remote observations are straightforward and the operation is robust. We expect to expand to a full seven days a week extended observing schedule soon into the New Year.  Extended observing will be used solely for JLS SCUBA-2 observations, and the hope is that with this enhancement the overall survey completion will reach closer to 90%.

 

Completing the JLS observations is only half the goal. The legacy value of these observations is dependent on the data being made accessible to the wider astronomical community. The JCMT Science Archive (JSA), supported by staff effort at the JAC and hosted at the CADC in Victoria, performs this function. Within the JSA there already exists a significant amount of publicly available data – both from SCUBA-2 and other JCMT instruments. The JAC and the CADC are committed to providing a suite of advanced data products for SCUBA-2 and HARP that will make it easier for the astronomical community to access and utilize JCMT data well into the future. At present, staff at the JAC are working toward tiled maps of the observed sub-millimetre sky using the HEALPix formulation and automated source catalogues of the structure within these maps. Further advanced products are expected to be produced by the individual JLS teams. Look for a more detailed discussion in the next JCMT Newsletter.

 

Unfortunately, the two Canadian-built ancillary instruments for SCUBA-2, the polarimeter (POL-2) and the Fourier Transform Spectrometer (FTS-2), were unable to reach a final commissioned state in time for the Semester 14A Call for Proposals and thus will not be used by PIs in 2014. These instruments were both designed and built to operate in conjunction with SCUBA-2, and both offer unrivalled observational capabilities. Their scientific potential is immense: wide-area mapping of magnetic fields and broad-band, moderate-resolution spectroscopy both hold great promise, particularly for galactic star-formation studies. Given that both instruments were developed in accordance with SCUBA-2's original design specifications, integrating them with SCUBA-2 as-built has turned out to be a fiendishly difficult technical problem. No showstoppers have been identified, and with more time it should certainly be possible to work through the technical issues. As such, the two ancillary instruments remain on the telescope and commissioning work continues on a best-effort basis.

 

It has been an amazing year working at the JCMT. When I began the position in November 2012, I knew the telescope well but only from an observer’s point of view. Over the last twelve months I have been warmly welcomed into the JAC family and have found an impressive work environment. Despite all the uncertainty around the future, the staff at the JAC remains dedicated and extremely proud of their JCMT. This culture quickly becomes contagious and I too will do what I can to keep this amazing telescope operating well into the future.

 
Doug Johnstone (d.johnstone@jach.hawaii.edu).