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DDT proposals

The ALMA Observatory is accepting proposals for Director’s Discretionary Time (DDT).

DDT proposals may be submitted at any time during Cycle 6, for implementation during this cycle. They must be submitted using a Cycle 6 specific Observing Tool, available through the OT link. The DDT proposals must belong to one of the following categories:

  1. Proposals requiring the immediate observation of a sudden and unexpected astronomical event (“immediate” should be understood as within a period of 3 weeks following their approval: the same time tolerance restriction applies to DDT proposals as to standard and ToO Cycle 6 proposals – see the ALMA Cycle 6 Proposer's Guide for details);
  2. Proposals requesting observations on a highly competitive scientific topic, motivated by developments that have taken place after the regular proposal submission deadline;
  3. Proposals asking for follow-up observations of a program recently conducted with ALMA or any other observing facility, where a quick implementation is expected to provide breakthrough results.


Preparation and submission of DDT proposals must be done in the same way as for regular Cycle 6 proposals: see Sect. 5 of the ALMA Cycle 6 Proposer's Guide for details. Note that proposal type “Target of Opportunity” should be selected for proposals falling into DDT category 1 above, and type “Standard” used for categories 2 and 3. In addition, the science case of DDT proposals must include a clear and strong justification stating why the project should be considered for DDT allocation and why it was not submitted as part of the regular Cycle 6 process. In the absence of such a justification, the proposal will not be considered for DDT allocation, and the proposers will be encouraged to resubmit it as part of the regular Cycle 7 process, for which a call for proposals is expected to be issued in 2019.

Cycle 6 policies are fully applicable to DDT proposals; in particular, DDT observations will be executed using the Cycle 6 capabilities and observing restrictions, as described in the ALMA Cycle 6 Proposer's Guide and documents referenced therein. However, the proprietary period of data obtained as part of DDT projects will be restricted to 6 months.

DDT proposals will be approved for execution by the ALMA Director, based on the advice of a small standing review committee, with members from the JAO and the four regions, appointed by the Executive Directors and Chile. In exceptional cases, the ALMA Director may approve projects that would benefit from a very rapid response, and inform the standing committee of this decision within 24 hours (but note the 3-week time tolerance restriction for Cycle 6 specified above). The science assessment of DDT proposals will be based on the same criteria as for standard and ToO proposals (see Sect. 3.5 of the ALMA Cycle 6 Proposer's Guide).

Given the limited amount of time available in Cycle 6 and the heavy oversubscription of this time by standard proposals, DDT proposals may be approved only if their science case is exceptionally strong, especially if they are not related to the observation of a sudden and unexpected astronomical event.

In Cycle 6, 200 hours on the 12-m Array and 150 hours on the ACA will be available for DDT proposals.

Approved DDT proposals will be added in a separate table to the published list of High Priority projects for each cycle.