• Proposal 552: Optimal Observing Strategies with ALMA when combining ALMA 12m, 7m & Total Power Array Data

  • Reviewer 6

Grade: 4.5

Title Optimal Observing Strategies with ALMA when combining ALMA 12m, 7m, and Total Power Array Data by Peter Teuben & collaborators

Alignment with NA ALMA Partnership strategic goals.

Increases the operating efficiency by optimizing the observing strategies for 7m, total power arrays, and optimizes scientific usage of sub-array modes. For the first case, I got the sense that this was creating a problem to solve. It doesn’t demonstrate that the current system is inadequate; surely it can be fine-tuned but a quantification of this would have strengthened the proposal.

Strength of the scientific case for the proposed ALMA upgrade concept. Comment on the relevance to the ‘ALMA 2030’ development documents.

The ALMA 2030 document mentions gains in speed, enabling efficient mapping, larger bandwidths. The component of the study on optimizing data combinations can fit into the first two of these, while the subarray tool effectively addresses the third, as it opens up larger bandwidths by sub-arraying. Quality of the upgrade conceptual design The project would result in suggestions for improvements to tools (OT) to optimize multi-scale observations, tool for ALMA array operators to optimize sub-array usage to optimize the resulting science. The design is well thought out and the plan is reasonable.

Readiness for production in the context of the ALMA Development Plan (the aim is to support a range of upgrades including both those which can be implemented rapidly and those requiring longer-term research and development).

The project utilizes previous work done as part of a cycle 4 study; the timing is reasonable and based on past performance of the PI, and should be ready for “production” (i.e., implementation @ JAO) in a reasonable amount of time after the study period ends. This of course is subject to schedules, resource allocations of partners and ability to implement any recommendations. Strength of the consortium organization (if applicable)

N/A Qualifications of the key personnel of the Study

Very qualified, both in the technical details of combining images from mm wavelength interferometers, expertise in mm wavelength observation from ALAM and other mm wavelength interferometers, and also in interfacing with NAASC, JAO.

Technical expertise, past experience (also in series production, if relevant) and technical facilities in the Institutes taking part in the Study.

Has been PI of several past ALMA development studies. Assessment of the level of risk inherent in the design

Low level of risk – the proposal identified only the speed of the tclean algorithm. There does not seem to be levels or frisk associated with other aspects of the study. Strength of the Scientific Team supporting the Study

Very strong, even though the contributions of individual members of the team are not spelled out explicitly. Brogan is a CASA subsystem scientist @ NRAO, can advise with aspects of image reconstruction in CASA, not clear what Mason’s contribution is; Koda was an expert visitor @ JAO in 2016; Mundy has experience with mosaic mapping, MEM reconstruction of single dish and interferometric data. Level of support guaranteed by the Institutes

Proposal mentions in-kind contributions from consultancy with NRAO, but no more detail is provided. Budgeted cost of the Study

Cost seems appropriate

  • Reviewer 8

Grade: 2

Title Optimal Observing Strategies with ALMA when combining ALMA 12m, 7m & Total Power Array Data

1. Alignment with NA ALMA Partnership strategic goals;

As it stands, ALMA is clearly far from optimized in the allocation of observing resources to projects that require the full spatial frequency range provided by the ACA. The addition of subarrays is likely to suffer similar problems in observing efficiency, unless strategies are carefully considered. Such inefficiencies area a significant, hidden, cost to ALMA operations. The proposers will perform simulations needed to rationalize observing time on the ACA for specific science goals, and also to try to rationalize practical aspects of subarrays for major use cases. Overall, this work will result in better ALMA science and less waste of observing time.

2. Strength of the scientific case for the proposed ALMA upgrade concept; Comment on the relevance to the ‘ALMA 2030’ development documents.

The motivation is strong for ALMA observing to be more efficient. In the Pathways document, work on image quality is a "low" priority, but the proposed work seems like a relatively fast and very inexpensive way for ALMA to produce better science. If there's a weakness, it's that the proposal does not quantify carefully the fraction of time currently devoted to projects that will benefit from the proposed work.

3. Quality of the upgrade conceptual design;

The proposers have the expertise and the tools to follow through on the work.

4. Readiness for production in the context of the ALMA Development Plan (the aim is to support a range of upgrades including both those which can be implemented rapidly and those requiring longer-term research and development);

The results of this study will have consequences for many observations that can be implemented immediately (with no down time).

5. Strength of the consortium organization (if applicable);

This is a good collaboration between community and key NAASC personnel.

6. Qualifications of the key personnel of the Study;

The key personnel have worked with similar imaging issues for years and are all highly qualified to tackle the problem. The NAASC personnel have the requisite experience with specific ALMA procedures, proposal tools, and imaging software. In addition, The NAASC personnel will play an important role in enabling the benefits of the study results to be realized by ALMA.

7. Technical expertise, past experience (also in series production, if relevant) and technical facilities in the Institutes taking part in the Study;

8. Assessment of the level of risk inherent in the design;

There is minimal risk. Essentially any result of this study will be better than what ALMA does now regarding optimizing observing time with the ACA for science.

9. Strength of the Scientific Team supporting the Study;

This is truly an expert team.

10. Level of support guaranteed by the Institutes;

Fine.

11. Budgeted cost of the Study;

The main cost is 0.5 FTE support for a highly experienced astronomy programmer, which seems reasonable for the proposed work. Additional support at a low level (.15 FTE) for the scientific leads is also necessary and reasonable.

  • Reviewer 9

Grade: 3.5

Title: 552 - Optimal Observing Strategies with ALMA when combining ALMA 12m, 7m, & Total Power Array Data

1. Alignment with NA ALMA Partnership strategic goals;

Directly aligns with goals 2.2, 4.2, 5.1

2. Strength of the scientific case for the proposed ALMA upgrade concept; Comment on the relevance to the ‘ALMA 2030’ development documents.

The scientific case is strong, well-motivated, and will likely lead to specific recommendations that will improve both the efficiency of the observatory and scientific quality of the data products.

The proposal indirectly addresses recommended development paths on “Gains in speed” and “Enabling efficient mapping.” While these development paths are mainly focused on larger bandwidths, increased receiver sensitivities, and increased mapping speed, they are partially addressed by this proposal aimed at determining the optimal observing time and map sizes when combining 12-m, 7-m, and TP observations.

3. Quality of the upgrade conceptual design;

Overall strong. The ACA is in high demand, as illustrated by the response to the recent call for supplemental cycle 4 ACA proposals. At present it is unclear if the fixed 12-m time multiplier is always required, and it is also unclear if the map sizes are sufficient to adequately recover emission over the relevant areas and physical scales. This proposal will investigate these topics, and the results can be directly fed into later versions of the OT, potentially increasing both the efficiency of the observatory and scientific return of the data. The second study goal of optimizing the sorting of antennas into subarrays is important, but the actual goals and work to be carried out are vague and underdeveloped.

4. Readiness for production in the context of the ALMA Development Plan (the aim is to support a range of upgrades including both those which can be implemented rapidly and those requiring longer-term research and development);

This project is in an intermediate stage - it will build on existing work from a cycle 4 development study in order to make specific recommendations that can be incorporated into the OT in future observing cycles.

5. Strength of the consortium organization (if applicable);

N/A.

6. Qualifications of the key personnel of the Study;

Very strong. The team has the expertise and experience necessary to carry out this project.

7. Technical expertise, past experience (also in series production, if relevant) and technical facilities in the Institutes taking part in the Study;

See #6 above.

8. Assessment of the level of risk inherent in the design;

There is no significant risk related to the primary study goal. It is difficult to assess risk in the secondary goal related to subarrays since this goal is not particularly well-developed.

9. Strength of the Scientific Team supporting the Study;

See #6 above.

10. Level of support guaranteed by the Institutes;

No comments of significance.

11. Budgeted cost of the Study;

The costs appear reasonable and appropriate. -- AlWootten - 2017-07-19
Topic revision: r1 - 2017-07-19, AlWootten
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