From kmenten at mpifr-bonn.mpg.de Wed May 3 15:51:45 2000 From: kmenten at mpifr-bonn.mpg.de (Karl Menten) Date: Wed, 3 May 2000 21:51:45 +0200 (MEST) Subject: [asac] ASAC Telecon on May 8 Message-ID: Dear ASAC members, The next ASAC telecon will be on Monday, May 8, at 21:00 UT (i.e. 23:00 Central European Summer Time, 17:00 Eastern Daylight Savings Time). As I will be out of email contact for the next few days, please send topics for discussion to Al Wootten (awootten at nrao.edu). Al will also email you instructions for phone access to the telecon. Cheers, Karl ----------------------------------------------------------------------------- Dr. Karl M. Menten (kmenten at mpifr-bonn.mpg.de) Max-Planck-Institut fuer Radioastronomie Auf dem Huegel 69, D-53121 Bonn, Germany Tel.: +49 (0)228-525297 * Fax: +49 (0)228-525435 From awootten at NRAO.EDU Fri May 5 16:15:14 2000 From: awootten at NRAO.EDU (Al Wootten) Date: Fri, 5 May 2000 16:15:14 -0400 (EDT) Subject: [asac] ASAC Meeting Monday, 8 May at 2100UT. Message-ID: <200005052015.QAA19317@polaris.cv.nrao.edu> The ASAC Meeting is next Monday, 8 May at 2100UT. There is a conflict next Monday for some people, as the NRAO Visiting Committee will meet in GB at about the same time as the ASAC phone meeting. I have placed a tentative agenda at: http://www.cv.nrao.edu/~awootten/mmaimcal/asac/mayagenda.html which includes the phone numbers, etc. I have suggested names for some people to cover materials which are hyperlinked to the agenda. Please check it. Thanks! Clear skies, Al +-------------------------------------------------------+ | Alwyn Wootten (http://www.cv.nrao.edu/~awootten/) | | Astronomer, National Radio Astronomy Observatory | | 520 Edgemont Road, Charlottesville, VA 22903-2475, USA| | (804)-296-0329 voice Let's build The Millimeter Array| | (804)-296-0278 FAX {> {> {> {> | +------------------------------^-----^-----^-----^------+ From awootten at NRAO.EDU Fri May 19 12:57:48 2000 From: awootten at NRAO.EDU (Al Wootten) Date: Fri, 19 May 2000 12:57:48 -0400 (EDT) Subject: [asac] National Academy of Sciences Recommends Continued Support of ALMA Message-ID: <200005191657.MAA16289@polaris.cv.nrao.edu> Contact: Rebecca Johnson, Public Information Officer National Radio Astronomy Observatory 804-296-0323 rjohnson at nrao.edu May 19, 2000 FOR IMMEDIATE RELEASE National Academy of Sciences Recommends Continued Support of ALMA Project A distinguished panel of scientists today announced their support for the continued funding of the Atacama Large Millimeter Array (ALMA) Project at a press conference given by the National Academy of Sciences. The ALMA Project is an international partnership between U.S. and European astronomy organizations to build a complete imaging telescope that will produce astronomical images at millimeter and submillimeter wavelengths. The U.S. partner is the National Science Foundation, through Associated Universities, Inc., (AUI), led by Dr. Riccardo Giacconi, and the National Radio Astronomy Observatory (NRAO). "We are delighted at this show of continued support from our peers in the scientific community," said Dr. Robert Brown, ALMA U.S. Project Director and Deputy Director of NRAO. "The endorsement adds momentum to the recent strides we've made toward the building of this important telescope." In 1998, the National Research Council, the working arm of the National Academy of Sciences, charged the Astronomy and Astrophysics Survey Committee to "survey the field of space- and ground-based astronomy and astrophysics" and to "recommend priorities for the most important new initiatives of the decade 2000-2010." In a report released today, the committee wrote that it "re-affirms the recommendations of the 1991 Astronomy and Astrophysics Survey Committee by endorsing the completion of . . . the Millimeter Array (MMA, now part of the Atacama Large Millimeter Array)." In the 1991 report "The Decade of Discovery," a previous committee chose the Millimeter Array as one of the most important projects of the decade 1990-2000. Early last year, the National Science Foundation signed a Memorandum of Understanding with a consortium of European organizations that effectively merged the MMA Project with the European Southern Observatory's Large Southern Array project. The combined project was christened the Atacama Large Millimeter Array. ALMA, expected to consist of 64 antennas with 12-meter diameter dishes, will be built at a high-altitude, extremely dry mountain site in Chile's Atacama desert. The array is scheduled to be completed sometime in this decade. Millimeter-wave astronomy studies the universe in the spectral region where most of its energy lies, between the long-wavelength radio waves and the shorter-wavelength infrared waves. In this realm, ALMA will study the structure of the early universe and the evolution of galaxies; gather crucial data on the formation of stars, protoplanetary disks, and planets; and provide new insights on the familiar objects of our own solar system. "Most of the photons in the Universe lie in the millimeter wavelength regime; among existing or planned instruments only ALMA can image the sources of these photons with the crispness required to understand the events of galaxy, star and planet formation which launched them into space," said NRAO's Dr. Alwyn Wootten, U.S. ALMA Project Scientist. ALMA is an international partnership between the United States (National Science Foundation) and Europe. European participants include the European Southern Observatory, the Centre National de la Recherche Scientifique (France), the Max-Planck Gesellschaft (Germany), the Netherlands Foundation for Research in Astronomy, the United Kingdom Particle Physics and Astronomy Research Council, the Oficina de Ciencia Y Tecnologia/Instituto Geografico Nacional (Spain), and the Swedish Natural Science Research Council. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. From awootten at NRAO.EDU Wed May 24 20:06:40 2000 From: awootten at NRAO.EDU (Al Wootten) Date: Wed, 24 May 2000 20:06:40 -0400 (EDT) Subject: [asac] Japanese participation in ALMA Message-ID: <200005250006.UAA13412@polaris.cv.nrao.edu> For the ASAC. The attachment referred to may be found at the WWW site at the bottom. Please let me know if you cannot get it. Al PLANNING FOR JAPANESE PARTICIPATION IN ALMA R. L. Brown (12 May 2000) 1. As we discussed at the last ASAC teleconference, the Japanese plans to become a third, equal, partner in ALMA are maturing at such a rate that the ACC has requested the AEC (Kurz, Guilloteau, Brown and Rafal) to develop plans for an "enhanced" ALMA that includes Japan as a partner. The plan should be done on the basis of potential science return, and to this end the AEC asks the ASAC to help. Specifically, we seek ASAC input in the form of a concise draft that prioritizes enhancements to the baseline ALMA seen as desirable by the ASAC. The draft (or the ideas to be in it) would be most useful if it were available by Friday June 23; this is a few days in advance of the time the AEC will meet with the Japanese group. 2. As input to the ASAC discussion I have attached a pdf file of the final report of the "ALMA Liason Group". This was given to the ACC at their April 2000 meeting. It summarizes a range of ideas presented by the Japanese group for possible ALMA enhancements. Ignore the references in this document to 'enhanced' and 'baseline' options. For those who have difficulty dealing with attachments, the file can be accessed at http://www.cv.nrao.edu/~cwhite/almaus/algreport.2000may12.pdf 3. In short, the goal is to discuss the makeup of a $552M+$552/2M = $828M ALMA, where the costs, or "value", of the parts are determined from the costing done for the US-European "baseline" project. What should be added to the $552M Project for greatest scientific benefit? [Don't worry at this point as to which partner would be responsible for delivering which specific instruments--the goal is to specify what is in the $828M array]. 4. Many of you may want to work from costs. Let's use these estimates for consistency starting from the "baseline": Management $24.6M Site Development 77.9 Antennas 212.4 Receiver Subsystem 92.6 LO Subsystem 36.1 Backend Subsystem 32.9 Correlator 16.9 Computing Subsystem 30.7 System Engin & Integration 21.3 Science Support 7.0 TOTAL $552.4M Some of the additional money to be brought to the project by the Japanese is spoken for. In particular the site infrastructure will be more extensive (+$30M?), the additional partner will have a 1/3 stake in the management, which now includes management of the project in Japan (+$12M?), System Engineering and Science will be more comprehensive again owing to the effort in Japan (+$10M?), and there will be additional backend hardware and perhaps a bigger correlator (+$15M). Let's assume a total of $66M goes for these things combined; this leaves us with something like $210M to add enhancements to the antenna and receiver/LO system. Now let's parameterize the Antenna and Receiver/LO costs so that we can add (and subtract?) from the array: If N_ant is the number of antennas in the array, and N_bands is the number of receiver frequency bands installed per antenna, let's use Antenna Cost = $20M + $3.0M*N_ant Receiver Cost = [$700k + $200k*N_bands]*N_ant LO Cost = [$200k + $100k*N_bands]*N_ant This makes a fully equipped (10 frequency bands) antenna cost $6.9M (including contingency, labor, materials, shipping, installation.....everything). 5. One of the possible enhancements to ALMA is an array of antennas of diameter smaller than 12m to be used to measure source visibility accurately on spacings ~10-15m that are not well sampled by the homogeneous array. If this idea is scientifically appealing, please address the following questions: -What is the diameter of those antennas and on what criteria is this choice made? -How many such antennas are desirable and on what criteria is this choice made? -Are the antennas fixed or moveable? (The ALG report speculates about putting them on rails so that the small array can be tailored to source declination--any value to this?) -Does the array of small antennas need to be correlated with the array of 12m antennas? (If so, the two arrays would have to be co-located). -If the array of small antennas does NOT need to be correlated with the array of 12m antennas then it can be located apart from the 12m array, and in particular it can be placed on a higher site, ~5300m, yet still in the Chajnantor science preserve. Any science value in this and the opportunity to observe at >1 THz it maximizes? To estimate the costs assume that the small antennas and their electronics have exactly the same costs as those for the 12m antennas given above (lessened economies of scale). 6. For those possible enhancements that overlap with tasks already part of the project (e.g. cryogenic systems, SIS fabricaton) it is enough to prioritize the contribution, we'll give it the same "value" as the same work done in the US or Europe. 7. For those tasks still ill-defined (e.g. the FX correlator and the photonics systems) it is again enough to prioritize the potential science benefit; we can work out the value to be assigned later. The ALG report is located at of the ALG Committee web site at URL: http://www.alma.nrao.edu/committees/ALG/algmarch2000rpt.pdf ------- end ------- From awootten at NRAO.EDU Fri May 26 11:48:02 2000 From: awootten at NRAO.EDU (Al Wootten) Date: Fri, 26 May 2000 11:48:02 -0400 (EDT) Subject: [asac] Questions from ALMA-SSR to ASAC Message-ID: <200005261548.LAA10250@polaris.cv.nrao.edu> ---------------------------------- D R A F T ---------------------------------- to ALMA Project Scientists and Alma Science Advisory Committee Members: ----------------------------------------------------------------------- Object: Project-wide issues of specific interest to Science Software Requirements During our past six months of work in the Science Software Requirements Committee we have encountered several issues on which we agree that further input on your side will be needed before our work can be completed. Our preliminary report (ALMA memo 293) has been recently officially reviewed and we take this opportunity to raise the following questions. These are mainly issues related to the way ALMA is operated as a whole. For each issue we would like to have either a definite answer or a baseline/fall-back alternative. The questions are given in order of decreasing importance. 1) Array Scheduling We have been assuming that ALMA will be dynamically scheduled so that each project is observed during weather conditions (seeing, opacity, wind) that allow its objectives to be achieved. This implies dynamic scheduling in near real time (Dynamic Scheduling) as stressed in mma memo 164, and in ALMA Project Book, Chapter 2(III.4). This has implications on the feedback from the PI, on the basis of calibration data and images produced by the pipeline: this feedback can only be offered at the end of one transit (observing session), assuming the project observations are divided into several transits either due to schedule optimization (as high elevations are preferred) or intentionally by the insertion of breakpoints. This limitation on `interactivity' has to be realized. We believe it is a small price to pay for the increase in productivity expected from dynamic scheduling. An alternate scheduling method is the traditional interactive observing, which should be available since it can be useful for test purposes and for special -- timely and unforeseen -- observations. Our question: Is dynamic scheduling to be the default mode of scheduling, accepting the restricted interactivity implied by this mode ? 2) Purpose of the pipeline The data flow ALMA Project Book, Chapter 2(III.5) will include a pipeline that may be used to fulfill several purposes: a) check that the data obtained can be calibrated, with feed back to the observing process to use the optimal phase calibration cycle. b) give feed back to the dynamic scheduler by monitoring the observed phase noise. c) produce calibrated uv data and maps of test quasars to check in real-time the quality of observations, with feed back to the dynamic scheduler. d) produce calibrated uv data and maps of the project source(s) to enable the PI to evaluate her/his data at the end of the observing session and to proceed with scientific interpretation when the project is finished (after improved reduction if needed), while incrementing the ALMA data archives. e) use calibrated uv data and maps of the project source(s) in order to derive simple quality parameters (noise level, signal to noise ratio) that may be used to define when the project goals are attained. f) use calibrated uv data and maps of the project source(s) in order to derive similar or more sophisticated parameters (source size, number of sources ... see examples in memo 293) to be fed back into the project's observing process, which may then take automatic decisions. While we believe that a, b, c and d should be implemented as baseline features, there is some concern that f) and maybe e) might be too ambitious goals (software has a cost too) or even may increase the distance between the astronomers and the instrument to an unwanted level. Our question: Which degree of sophistication should be set as a goal for the ALMA data pipeline ? 3) Operational aspects For the specification of GUI (graphical User Interfaces) a clear description of the relative duties of the operators and local staff astronomers will be needed, in view of the following tasks - Allocation of antennas to simultaneous projects (e.g. a sub-array for calibration, a sub-array used for astronomy, some antennas in maintenance) ? - Control on the dynamic scheduling process - Communication with the PIs if needed Our question: Can the relative duties of the staff in charge of controlling the array be already outlined ? 4) Policy on data propriety: We are assuming, as is the usual practice in most observatories, that only the proposing team has access to the data during a limited proprietary period and that the data ultimately become public. The actual length of the propriety period can be probably be set later, but some policy questions may affect the software requirements, such as: 4.1 is only the scientific data covered, or all header information including monitoring data, or some header information only (like coordinates and frequencies) ? 4.2 if public data is reprocessed in the pipeline by others, to search for unforeseen scientific results, does this start a new proprietary period ? Our question: Can the proprietary data policy of ALMA be already outlined ? 5) Special modes Some specific observations (Sun, Pulsars, ...) may need very short integration times, fast frequency changes, ... for which the exact scientific software (and hardware ?) requirements need to be investigated in detail. For these issues we would like having specialized astronomers as correspondents, so that we may include their contributions in our requirements, in a coherent manner. 6) Other details - is an audio channel from the antenna cabins to the operator planned ? (see comment 95) - We assume, as DSB mode is clearly an option for some frequency bands, that side band separation has to be handled by software for interferometric work in those bands. Robert Lucas, on behalf of the Science Software Requirements Committee