DDT proposals
The ALMA Observatory allocates up to 5% of observing time per Cycle to Director’s Discretionary Time (DDT) proposals. These are submitted outside the standard proposal review process and are approved at the discretion of the ALMA Director. DDT proposals are open to all scientists worldwide.
General Principle
DDT proposals are intended for projects of compelling scientific merit that fall within the defined categories below. They should represent opportunities that could not reasonably have been anticipated or proposed during the main ALMA Call for Proposals.
Eligible Categories
DDT proposals must fall into one of the following categories:
- Target of Opportunity (ToO)
- Observations of unexpected, short-lived astronomical events with compelling scientific value.
- Urgent High-impact Science
- Observations motivated by recent scientific developments that justify prompt ALMA observations and have the potential for significant scientific impact.
Proposals Not Suitable for DDT
The following types of proposals are not suitable for DDT submission:
- Resubmissions of proposals that were rejected in a recent Call or a previous DDT submission, unless there is substantial new information.
- Proposals that could reasonably have been submitted during a main Call, including predictable or recurring ToO requests.
- Observations without compelling scientific urgency that would be more appropriately submitted during the main Call for Proposals.
Required Proposal Contents
In addition to the standard components outlined in Section 5 of the current ALMA Proposer's Guide, DDT proposals must include a section addressing the following points.
- DDT justification: Explain why the proposal qualifies for DDT, describing the compelling scientific merit and the unanticipated or time-critical nature of the opportunity.
- Timing rationale: Explain why the proposal could not have been submitted during the main Call for Proposals and why consideration through the DDT process is warranted.
These elements will be evaluated according to the criteria described below under Review and Evaluation.
Submission Instructions
DDT proposals must be prepared and submitted using the Cycle 13 ALMA Observing Tool (OT - linked below), following the same procedure as main Call proposals (see Section 5 of the ALMA Proposer's Guide). Joint Proposals and Large Programs are not eligible for DDT.
Review and Evaluation
DDT proposals are evaluated using the same criteria as main Call proposals (see the ALMA Proposer's Guide), with the following additional considerations:
- DDT scope: The proposal must clearly fall into one of the defined DDT categories.
- Urgency: Demonstrate that the proposed observations require prompt consideration through the DDT process and could not have been anticipated or proposed during the main Call for Proposals.
- Uniqueness: Proposals that duplicate observations already accepted in the queue or proposals currently under review in the main Call for Proposals may be returned without scientific review.
DDT proposals are reviewed by a standing committee composed of members from the Joint ALMA Observatory, the ALMA Regional Centers, representatives from the ALMA regions, and Chile. The ALMA Director makes the final decision based on this advice. Decisions are normally communicated within two weeks. In urgent cases requiring immediate action, approval may be granted by the ALMA Director within 24 hours.
Proprietary Period
DDT proposals submitted after the start of Cycle 13 on 1 October 2026 will have no proprietary period by default. Data from approved projects will be released to the public immediately after the data are delivered to the Principal Investigator.
If a proprietary period of up to six months is required, it must be requested at the time of proposal submission via a Helpdesk ticket. The ticket should be submitted to the Proprietary Extension RequestsHelpdesk department within 24 hours after submitting the proposal and must include:
- The DDT proposal code,
- The length of the requested proprietary period (up to 6 months),
- A clear justification for the request.
Requests for a proprietary period will be granted only in exceptional circumstances. The ALMA Director will make the final decision, and any approved period will be specified in the acceptance letter.
ALMA Observing Tool
The ALMA Observing Tool (OT) is a web-based application consisting of a set of user interfaces that are needed to prepare and submit an ALMA observing proposal. The current Cycle 13 release of the OT is configured for the present capabilities of ALMA as described in the Proposer's Guide. Note that in order to submit proposals you will have to register with the ALMA Science Portal beforehand.
Cycle 13 OT
The OT is supported on the latest versions of the web-browsers Chrome, Firefox and Safari. To access the OT just click on the logo:
Documentation
Extensive documentation is available to help you work with the OT and optimally prepare your proposal.
- We recommend our novice and advanced users to start with the OT video tutorials which give audio-visual illustrations of different aspects of the web-based OT.
- More in-depth information on the OT can be found in the User Manual, while concise explanations of all fields and menu items in the OT are given in the Reference Manual.
Troubleshooting
If you have questions about the web-based OT, please visit our 'FAQ and Known Issues' page first. The page also contains a list of currently known bugs and possible workarounds. A further source of information is the OT section of the ALMA Helpdesk Knowledgebase - this contains a number of articles that also deals with frequently-asked questions. After exploring these resources, if confusion over some aspect of the OT remains, or if a previously unidentified bug has been uncovered, please file a Helpdesk ticket.