NTAC Proposal Evaluations

Similar to other time allocation committees, the NTACs must evaluate their communities' proposals for scientific merit and technical feasibility. However, because the overwhelming majority of Gemini observations are queue scheduled, the NTACs should also consider "strategic feasibility" of the forwarded proposals, which is a strong function of the proposals' ranking. Here we list some important issues for your consideration.

• The Call for Proposals

  Consider the guidelines and restrictions provided in the Gemini Call for Proposals. These include restrictions on target accessibility and instrument availability.

• Keck or Subaru Exchange Time

  Subaru or Keck classical proposals must have a total request of integer nights or 10 hours. For Keck and Subaru there are restricted allocation windows as described in the Call for Proposals and the program must contain targets that are appropriate for these times; note that no dark time is available on Keck. Keck proposers are required to complete the Keck cover page which should be emailed by the PI to their NTAC. Please forward all Keck and Subaru proposals, as pdfs, to the Gemini ITAC Chair for technical assessment at these observatories.

• Classical-Mode Gemini Proposals

  The Gemini classical nights recommended by each partner will be removed from the partner's queue allocation before the queue merge is carried out, and so these should be highly ranked programs. Proposals requiring unusually good observing conditions (e.g. thermal programs requiring dry weather) or containing targets with widely distributed RAs, should be executed in the queue and not as classical nights. The total time request must be integer nights or 10 hours. A backup program that can be done in poor conditions should be specified; if the conditions specified are rare and no backup is specified it is likely that the allocated time will revert to queue.

• Science Ranking of Queue Proposals

  The three science ranking bands for queue proposals are defined to be 0-30%, 30-60% and 60-100% of the available queue time at each telescope. The available queue time is the advertised time on each telescope, less the time required for classical programs, and less the time estimated to execute rollover programs accessible in the semester. The rollover time is typically 5% of the advertised time. When estimating where in your NTAC-ranked queue-program list the band divisions will fall, do not assume that these will be 30% and 60% of the advertised partner time. First subtract your requested classical time from your allocation, and then estimate the band 1/2 and 2/3 divisions at the conservative side of the 28% and 57% time boundaries, to allow for rollover time and the vagaries of filling the queue. If you have a program that must fall in band 1 make sure it is in the top ~25% of your available queue time, and if you have a program that cannot be in band 3 make sure it falls in the top ~55%. Rapid Target of Opportunity proposals must fall in Band 1, and LGS programs must lie in Bands 1 or 2.

  Band 3 programs need special attention and programs that fall below 55% of your allocation may fall in Band 3. First check that the PI has not selected "Do not schedule in Band 3". If they have but you think they can produce useful science and will accept Band 3 time, then inform the ITAC Chair, otherwise promote or drop the program. Next, examine proposals that have tight observing or timing constraints, those that use uncommon GMOS configurations, or those that have RAs historically in heavy demand. Such programs are very unlikely to get data and should be promoted or dropped. Technical assessments must be done on both the main program as well as the modified program described in the Band 3 tab.

• Joint Proposals

  Joint proposals are evaluated by each NTAC to which the proposal was submitted (each "joint component"). The final ranking of the joint proposal in the merged queue is a time-weighted average of the individual rankings (that is, a normalized average of each partner's rank scaled by the time allocated by that partner). The final disposition of joint proposals is not decided until the ITAC, when each partner learns the disposition of each of the other joint components. NTACs should take care to provide instruction to their ITAC representative how the joint proposal should be handled based on what the other NTACs have decided. For example, if a joint proposal is not supported by one or more other partners, should the ITAC member drop support, or add time to reach a certain minimum level? The "minimum useful time" (indicated in the PIT) can be very useful in making these decisions as the sum of the "minimum useful time" from each component should equal the minimum time required to execute the program. NTACs must forward to ITAC all Joint proposals whether recommended time or not, so that all Joints are recognized as such and properly considered.

• Target of Opportunity Proposals

  ALL proposals that do not have pre-defined targets (i.e., unknown coordinates) MUST have one of the "Target of Opportunity" boxes checked in the PIT XML file. Target of Opportunity (ToO) programs are defined as "Standard" or "Rapid" trigger, depending on the necessary response time. All ToO programs are reviewed during the ITAC process to check for duplication or conflict.

  Rapid ToOs (immediate or less than 24 hour response time) programs must be ranked in Band 1 to be recommended at the ITAC and so should be in top 25% of your rankings. The most common type of rapid ToO is Gamma Ray Burst follow-up observations. Only one GRB program can be active at any given time, and only one, or possibly two, such programs per telescope will be recommended by the ITAC. (If it is two, the Head of Science Operations for that telescope will work out an "activation schedule" with the two teams involved.)

  Standard response ToO programs (response time > 24 hours with no guaranteed upper limit) may be in any band, however their ToO status does not afford them any special priority. That is, a Band 3 ToO program will not be executed before Band 1 or 2 just because it activates a target. For a highly ranked program, a typical standard response time may be 2-3 days, however a program in Band 3 could have a much longer response time, or not be observed at all. The NTACs should assess the nature of the ToO proposal and be sure that its ranking is consistent with the needs of the program. Some ToO programs (e.g. following up survey targets) can obtain data at any time, while others may not require <24 hr response but will still be time critical (3-5 days for a supernova for example) and so would not be appropriate in Band 3. Any ToOs in Band 3 will be specifically evaluated at ITAC.

• RA Distributions

  The RA distribution of the program set forwarded to ITAC should approximately follow the availability for the semester. Historically in the North in the A semester the RA range 10 - 14 hours has been oversubscribed, and in the B semester RA~4 hours can be a problem. We cannot complete programs if the the RA distribution does not track what is available.

• Observing Constraints

  It is essential that the observing constraints are correct for properly filling the queue. LGS programs require IQ70 CC50 or better, and dark or grey skies if the guide stars are faint; NGS-AO usually requires IQ70; NICI programs require IQ70 CC70 or better; thermal IR usually requires WV50/80 and SBany; optical usually requires WVany and SB50/80. If these are not selected then check and correct as necessary. If CC90/any or IQany have been selected check that this is realistic and not an error.

  Forward to ITAC a set of programs that match the occurrence of the various constraints, as far as possible. That is, no more than 50% should require CC50 etc. CC50 is the constraint that is usually filled first so lower ranked programs should require CC70 or worse. Try to have 20% of your allocation in CC90 low-ranked programs.

• Poor Weather Programs

  Poor weather programs can be submitted either via the regular 6-monthly Call, or, at any time, directly to the Observatory using the Phase I Tool. If submitted via the regular Call, the TACs must rank the program in the normal way. If the program ends up as a science program in Bands 1-3 it will be executed before any Poor Weather queue programs. If submitted directly to the Observatory, and approved, the program only exists in the Poor Weather queue. There are very few programs that can be done in poor weather, and so the chances of getting data from the Poor Weather queue are quite good. If a program qualifies as a poor weather program (and is to be considered as one), the "Poor Weather Candidate" flag must be checked in the "TAC" section of the Phase I Tool (PIT) XML file. If the program is ranked high enough to achieve Band 1, 2 or 3, it will be included in the queue as a regular program, otherwise, if it has the "Poor Weather Candidate" flag set, it will be added to the poor weather queue (i.e., Band 4). No time is deducted from the partner's allocation for Poor Weather programs and there is currently no limit to how many poor weather programs can be submitted by the NTACs, regardless of partner share. This means that poor weather programs can overfill a partner's time allocation, at the bottom of the partner's ranked list, but they should still be ranked (relative to each other) in case not all of the poor weather programs are accepted. The "poor weather queue" is reviewed during the ITAC meeting and modified if necessary.