REPORT OF THE CASCA RADIO ASTRONOMY COMMITTEE June, 1997 In the past six months, the radio astronomy committee had a formal meeting (via teleconferencing) and many e-mail exchanges. The main points discussed at our meeting were: 1. The NSERC reallocation exercice and 2--the radio spectrum protection. For the first point, a separate document will be sent to J. Landstreet. For the second point, a document has been prepared by Rob Roger for distribution at the next CASCA meeting. Rob Roger, who just retired from HIA and who was the Canadian representative for the radio spectrum protection issues will be replaced by Ken Tapping. The following report will try to summarize the {main} activities of the radio astronomy community under the following headings: * NRC Committee Report on the Future of Radio Astronomy in Canada * Future of Radio Astronomy in Canada -- Follow-up work (SKA & LAR) * The Canadian Galactic Plane Survey (CGPS) * News from DRAO * News from the JCMT * Space VLBI ---> NRC Committee Report on the Future of Radio Astronomy in Canada After two years of work and a special forum at the last CASCA meeting (Kingston), the NRC Planning Committee for a New National Facility for Radio Astronomy (E. Seaquist, C. Carignan, P. Dewdney, R. Taylor, C. Wilson) submitted its second and last report to the HIA Director, Don Morton in December 1996. In assessing priorities for Canadian involvment in an international project, the Committee considered the fulfillment of the following conditions as essential: * The project must be scientifically exciting. * It must have broad, though not necessarily unanimous, community support, and the direction taken must be identifiable with a ``grass roots'' thrust. * It must be firmly grounded in available technical skills, providing for ``full intellectual participation'' by Canadian astronomers. The main recommendations of the committee were the following: 1-- Canada should adopt the SKA as its highest priority for a new national radio astronomy facility, and should now contribute to an international effort assessing its feasibility and to providing its share of the innovative technology needed to build the telescope. This priority should be rigorously reassessed in the year 2000, and altered if necessary. The reassessment is necessary in view of a number of remaining unknowns, including the technical feasibility of the SKA. 2-- Given Canada's existing investment in sub--mm astronomy through partnership in the JCMT, the JCMT group should give its highest priority now to a leading technical role in linking the JCMT to the forthcoming Submillimetre Array (SMA) under construction on Mauna Kea by the Harvard--Smithsonian Observatory. 3-- NRC and Universities should cooperate in both of the above initiatives in order to provide sufficient ressources, and to permit a re--vitalization of engineering skills in radio astronomy within the university sector. ---> Future of Radio Astronomy in Canada -- Follow-up work (SKA & LAR) Work on plans for Canada's future in radio astronomy began in July 1994, with the appointment by the HIA Director General of Peter Dewdney as co-ordinator of future radio astronomy projects. Bruce Veidt was hired as a Research Associate in March 1997 to assist Peter Dewdney with this work. The main task of Dewdney & Veidt is to follow the development of the Square Kilometer Array (SKA) via the international working group on the future large cm radio telescope and to work at developing a Canadian concept in order to provide enabling technology for the SKA based on the pioneering work of Tom Legg on the Large Adaptive Reflector (LAR) concept. Peter Dewdney should also continue to follow the developments of the main large mm and sub--mm projects. Following the recommendations of the report to the astronomical community from the NRC committee, investigations on the feasibility of the Large Adaptive Reflector have begun. Three reports have been issued on the feasibility of a tethered balloon as the vehicle to support the focus equipment. Wide consultation on technical issues has taken place between the DRAO group and Canadian industry and academic researchers. At the end of February, Dewdney & Veidt produced a document describing the specifications and guidelines for research in the critical development areas of the LAR. They outlined the main three phases of the feasibility studies namely: phase A -- the detailed paper design study, phase B -- the preparation for a prototype and phase C -- the prototype demonstration. They also described in detail the requirements for the different sub--systems of the LAR, namely: the airborne platform, the reflector, the measurement systems, the control systems and the feed system. The promise of this technique is to allow the construction of very large antennas (e.g. SKA) at a relatively low cost per unit of collecting area. If this is achieved, this would allow Canada to have a leading role in the definition of the next large cm telescope. Following the NRC committee recommendation, a group of scientists and engineers from NRC and Canadian universities and industries was assembled to carry out those technical studies of feasibility for the LAR concept. They submitted a grant application to NSERC (under the NSERC/NRC Partnership Program). The PI is Russ Taylor from the University of Calgary. The group includes 13 researchers from 7 engineering departments from Canadian universities, 3 engineers from 2 Canadian companies, and one US company. In addition, 10 Canadian scientists have joined the proposal as scientific advisors. Five members of the DRAO staff are co-applicants, and will be actively engaged in this research. One graduate student, from the Electrical Engineering Department at the University of Alberta, is already at work at DRAO on a research project for the LAR. ---> The Canadian Galactic Plane Survey (CGPS) The project formerly known as "the Galactic Plane Survey" has been renamed the "Canadian Galactic Plane Survey" by the project's management committee after pressure from the editor of the Astrophysical Journal, who objected to the use of the acronym GPS, since this is widely used with another meaning. Observations for the CGPS began in March 1995, and have been proceeding smoothly. During the first year many technical problems were solved, both on the telescope and in the data processing area, leading to considerable improvement in image quality. The second year has seen the publication of some exciting science results from the Survey, including the discovery of a galactic "chimney", a region where the strong winds from an association of massive stars has blown a hole through the galactic disk. Observations for the CGPS are the main focus of the DRAO Synthesis Telescope. A total of 76 CGPS fields have now been observed, out of 190 in the planned survey area. This is 40% of the area in 43% of the allotted time. Data processing to the raw image stage is able to keep up with the observing schedule, but the higher level data processing is a little behind. The more sophisticated data processing work is carried out by Research Associates on the DRAO staff, and one funded from the NSERC grant to the CGPS. With the experience of the first two years, robust procedures have been developed, and it is expected that image production will gradually catch up with observing. A first distribution of CGPS data to the consortium was made in December 1996 on CDs. A visualization package has been developed at DRAO and is now being maintained by the consortium through the efforts of a post-doc based at the University of Calgary. An important part of the CGPS data will be provided by the DRAO 26-m telescope, which provides the "short baseline" data that are not observable with the interferometer. For this purpose, the 26-m Telescope has been equipped with a new spectrometer, identical to that used on the Synthesis Telescope. At the same time the telescope control software has been rewritten and the receiver linearity and stability has been improved. Coverage of the survey region requires the acquisiton and processing of about 25,000 spectra. This work is about 10% complete, and is expected to be substantially complete by the fall of 1997. Most unique to the CGPS data are the high resolution, panoramic images of polarized emission from the Galaxy, which provide a powerful method for probing the structure of the magnetic field and electron density in the ISM. A number of unusual polarised features, at both large and small scales, have been discovered. No phenomenon implying such large scale organisation of magnetic field and electron density has ever before been observed in our Galaxy. The members of the consortium (NRC and Universities) are divided in various research teams and are already using the available data to study the following topics: the disk-halo interaction, dissociating stars, characterisation of HI features, HI associated with neutron stars, HI associated with planetary nebulae, star formation, stellar winds & SNRs. A theory group has also been formed at the last CGPS meeting. ---> News from DRAO Following the Federal Budget of March 1995 and the subsequent review of NRC programs, there have been major changes at DRAO. The Synthesis Telescope changed in nature from an open facility to a project-oriented telescope, dedicated almost exclusively to the Canadian Galactic Plane Survey. In the last year, only 5 non--CGPS fields were observed for external observers. A description of the CGPS is given elsewhere. Layoff notices were given to seven staff members (about one third of the staff) with departures spread between October 1995 and March 1998, and plans were made to end observing at DRAO in April 2000 and to close DRAO in April 2001. The work force at DRAO has not actually shrunk since 1995, but it has changed substantially. The number of staff in continuing positions is now less than half the complement. The others are either in NRC positions of limited duration, or are supported by other "soft" money. In the summer of 1997, the number of people working at DRAO, including students and long-term visitors, is about 35. There are many new developments at DRAO of wide significance to Canadian radio astronomy. Since March 1995 three of the above programs, Space VLBI, the JCMT Correlator project, and the definition of the future of Canadian radio astronomy, have risen significantly in the level of effort they receive at DRAO. The JCMT Correlator project has been started from scratch. To be able to shift effort to these new endeavours while maintaining existing service from the Synthesis and Solar Telescopes, and at the same time facing the realities of a shrinking staff, has been a major challenge. Through the latter part of 1996, HIA negotiated a contract with the JCMT organization to build a correlator in Canada for focal-plane array spectroscopy. A proposal to build the correlator in Penticton and Victoria has now been accepted. The system design, digital engineering and software development will occur at DRAO. IF input circuits will be designed and built by a member of the JCMT group in Victoria. The Solar Flux monitoring program at DRAO is the continuation of a series of observations that have been made by NRC for fifty years. The measurement, the total radio flux density of the Sun at 2800 MHz (wavelength 10.7 cm), is used worldwide as an important indicator of solar activity. The value of the database lies in the choice of wavelength, which gives information on a key region of the solar atmosphere, and in the quality and consistency of the measurements over a long period. Over the past year the automation of the measurement process has proceeded. The operation is now folded in with the operation of the other DRAO telescopes, and requires a total of one person of effort spread over a number of individuals. Despite all this service activity, research continues at DRAO. Between April 1996 and April 1997 41 papers were published by DRAO staff members. In August 1996, DRAO hosted the Second Naramata Summer School on the Interstellar Medium at Naramata, with additional funding from HIA and from CITA. The School was very well received. Fifteen lecturers spoke to an audience of 22 graduate students, 7 postdocs, 5 undergraduates, and 10 research scientists in established positions. Most attendees were from Canada. ---> News from the JCMT The JCMT continues to establish itself as a world-class facility and this is reflected in the number and quality of papers based on JCMT data. In 1996, 51 papers were published in refereed journals and 10 of these involved Canadian authors. Currently the overall telescope over-subscription rate is about four and the Canadian rate is 3.6. The instrumentation on the JCMT continues to work well. The big news is that the problems that have beset the SCUBA project have finally been overcome and that the performance meets specifications. Observations are now being made in the serviced mode. Receiver B3 (320-360 GHz) has been successfully commissioned and apart from a few minor problems is performing well. The performance of one of the two mixers (channel A) is poor at frequencies below 340 GHz and it will be replaced in the fall. The former B-band receiver B3i has been returned to the HIA to be refurbished as an A--band receiver to replace A2. It is expected to be returned to the JCMT in the late summer. Receiver W has been delayed and is now due for delivery in the autumn. Short-baseline interferometry between the JCMT and the CSO has continued and 183 GHz water-vapour radiometers which monitor the phase difference between the two telecopes have been installed. There are a number of new instrumentation projects being considered for the JCMT. Once receiver W is commissioned, receiver C2 will be converted to cover the E band (800-900 GHz), the highest frequency available on the telescope. A B--band array receiver and associated correlator are in the early design stages as is a specialized very broad-band receiver for the observation of highly redshifted lines. In addition a multi-year program to upgrade the JCMT receivers has been approved by the Board and a polarimeter for SCUBA is under construction. Future plans for the observatory also include the exciting possibility of linking the JCMT to the Harvard--Smithsonian submillimetre array. This will be achieved by modifying the existing suite of receivers and should be ready for observations at the end of 1999. This project promises to provide Canadian radio astronomers with a stepping stone to participation in a next generation mm/submillimetre array project. There are several areas in which the telescope infrastructure is being improved. The telescope control system is being converted from a VAX to a UNIX based system to improve efficiency and flexibility. The surface accuracy is being improved by building a more accurate holography receiver and developing an active surface control system to counteract the large thermal distortions that occur in the morning and evening. These measures should improve the surface accuracy to 22 microns RMS. Improvements to the azimuth track such as levelling the track and improving the stability of the joints have been completed. JCMT staff are conducting a detailed study of the cost and feasibility of implementing fully remote operation of the telescope. The main objective is to cut costs and to allow flexible scheduling. The JCMT Group of the HIA relocated from Ottawa to the HIA/DAO site in Victoria last summer. A new laboratory has been set up and is now operational. Two new staff members have joined the group. Keith Yeung will be working on receiver and correlator electronics while an NSERC fellow, Dr Stephane Claude will be working on the development of SIS mixers. ---> Space VLBI In December 1995 the Canadian Space Agency officially joined the VSOP Space VLBI mission, and funding was provided to operate the correlator for this project at DRAO for the duration of the mission. The operation is also supported by Natural Resources Canada. The other Canadian partners in this effort are the Institute for Space and Terrestrial Science (ISTS) at York University, and the Physics and Astronomy Department at the University of Calgary. ISTS has developed the S2 recorder system, which has become a small export industry for Canada. The University of Calgary is providing the imaging capabilities to support Canadian scientists using VSOP. Canada has been allocated a major share of the bright-source survey which VSOP will undertake. There will be three correlators for this project, one in Japan and one in the USA, in addition to the DRAO correlation centre. DRAO will be the centre where all S2 data will be correlated, and staff at DRAO will manage the worldwide distribution of tapes for telescopes using the S2 recording system. During the last year the Space VLBI Correlator has been completed, and has moved into an operational mode. The 8--m orbiting antenna was launched from Japan in February 1997, and testing of the entire VLBI system is proceeding. The DRAO correlator has successfully found fringes from many baselines involving ground-based telescopes. Fringes have been found by the Japanese correlator on baselines including the spacecraft, and the DRAO group is actively searching for fringes on these baselines. Geophysical VLBI observations, made by Natural Resources Canada, will also be correlated at DRAO. Claude Carignan optimized at 450um. These arrays are simultaneously imaged