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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:

  1. Target of Opportunity (ToO)
    • Observations of unexpected, short-lived astronomical events with compelling scientific value.
  1. 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 ALMA Observing Tool (OT), 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 12 on 1 October 2025 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 Java desktop application used to prepare and submit ALMA Phase 1 proposals, including DDT proposals. The current release of the OT reflects the present capabilities of ALMA as described in the Call for Proposals. To submit proposals, users must first register with the ALMA Science Portal.

 

OT Download & Installation

The OT should run on all common operating systems and depends on a version of Java being available. The Cycle 12 can only be installed manually with a tarball distribution, as an installer is not available. 

The tarball version and the instructions for its manual installation can be found clicking on the button:

     tarball_button

OT Documentation

Extensive documentation is available to help you work with the OT and optimally prepare your proposal:

  • If you are a novice OT user you should start with the OT Quickstart Guide, which takes you through the basic steps of ALMA proposal preparation.
  • Audio-visual illustrations of different aspects of the OT can be found in the OT video tutorials. These are recommended for novices and advanced users alike.
  • 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. These two documents are also available within the OT under the Help menu.

 

OT Troubleshooting

If you have problems with the OT, particularly with installation and/or startup, please see the troubleshooting page. A list of currently known bugs, their status and possible workarounds can be found on the regularly updated known OT Issues page. A further source of information is the OT section of the ALMA Helpdesk Knowledgebase - this contains a number of articles that deal 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.