By / par Chris Wilson (McMaster University, JCMT Board Member for Canada)
(Cassiopeia – Winter / hivers 2020)
Canadian PI Proposals Return for 2021
Five Canadian universities (McMaster, Alberta, Queen’s, Manitoba, and Montreal) are contributing some funds towards JCMT operations in 2021. ACURA has also contributed some funding and HAA has a separate contract to purchase observing time in 2021. As a result, researchers at all Canadian universities are once again eligible to apply as PIs for observing on the JCMT.
The special 2021A call in the fall led to a healthy oversubscription rate. The 2021B call for proposals will be released in February with proposals due in March 2021. Band 5 weather contains to remain undersubscribed and counts as “free” in the time-allocation process and so I especially encourage proposals that can use this weather band.
The replacement 230 GHz receiver called Namakanui has been made available for shared-risk observing as of semester 2020B. This receiver is on loan from ASIAA (Taiwan) and is the spare receiver for the Greenland Telescope. It is a 3-band receiver design; the 230 GHz-band cartridge is known as U’u.
Please note that I expect semester 2021B to be the last time that Canadians will be able to apply as PIs for regular observing proposals. After that time, Canadians will be able to access PI time by collaborating with our colleagues in the U.K. or the EAO partner regions (China, Japan, Korea, and Taiwan) to see if they would be interested to partner on a proposal. Band 5 weather contains to remain undersubscribed and counts as “free” in the time-allocation process.
The fact that the CADC continues to host the JCMT data archive is maintaining our access to JCMT large programs. Several new large programs were approved and began collecting data in 2020. Descriptions of the approved large programs are available here.
Observing
The JCMT was shut down for just over two months from mid-March to end of May due to COVID-19. However, since that time the observatory has returned to more or less normal operations. This has been facilitated by the fact that the JCMT has been observing fully remotely (from a control room in Hilo) since November 2019. I anticipate the observers and students will once again be welcome to visit to observe from Hilo and to visit the telescope at the summit once the pandemic is under control.
Science
There have been a number of high-profile results from PI programs on the JCMT over the past several months. Probably the result to get the most press coverage was the publication of evidence for phosphine in the atmosphere of Venus (Greaves et al. 2020, Nature Astronomy). The original observations were carried out with the JCMT and were followed up with ALMA. The importance is that phosphine in this instance provides hints of life in Venus’s atmosphere; however, subsequent papers looking at the ALMA data have called the detection into question. Perhaps something that JCMT can follow up with the new, more sensitive U’u receiver in the near future?
A second very interesting result from the Event Horizon Telescope team shows that the shadow of the black hole in M87, Powehi, seems to be wobbling on a timescale of ten years (Wielgus et al. 2020, ApJ). The crescent-like feature that was imaged in 2017 seems to be persistent, which implies it is a real effect caused by light bending from the black hole. The wobble gives us information on how gas is flowing around the black hole.
Finally, JCMT observations of the star Betelgeuse have revealed that its recent unprecedented dimming was most likely not due to a passing dust cloud but to the development of signicant starspots which affected its brightness (Dharmawardena et al., 2020, ApJL). This prominent star in the constellation Orion began to decrease in brightness in October 2019, and ultimately became roughly 3 times (1 magnitude) fainter than normal until it eventually returned to its original brightness. The JCMT images showed that Betelgeuse became 20% dimmer at submillimetre wavelengths, inconsistent with a foreground dust cloud but consistent with lower-temperature starspots covering 50-70% of its surface.
No Success with CFI for New 850 Micron Camera
A team of Canadian universities led by McMaster submitted a proposal for the CFI 2020 Innovation Fund competition to seek to contribute funding to constructing a new 850 micron camera for the JCMT. Unfortunately, this proposal was not successful. However, the observatory is still moving ahead with the development of this new camera, which is planned to have 20 times faster mapping speed than SCUBA-2 with dual-polarization capabilities.
