After the proposal deadline, submitted proposals may not be changed prior to the completion of the proposal review process.
Major changes (Appendix B of the ALMA User Policies) are allowed only if the change is essential for the science goals of the project. Please see the "What is the definition of a Major change?" KB article.
Any major change request by a PI must be made by submitting a Helpdesk ticket through the "Proposal Change Request" department and will only be implemented after the approval of the change request. Please make sure to fill out all fields on the Helpdesk ticket when submitting the request.
Please see the Changes to ALMA Proposals section in the ALMA User Policies Document.
Major change requests may be motivated by the following considerations:
• New information received since the original proposal submission (e.g. new observations including interim observational results of a project, other new information on planned observing targets, or externally-imposed changes to the scheduling of time-coordinated observations at other observatories)
• Technical considerations for implementation during Phase 2 (that are initiated by the PI, e.g. to optimize the scientific yield of the observations)
• Mistakes made by the PI.
A PI-initiated change request is not necessary in the following circumstances:
• To correct errors introduced by the Observatory (either by ALMA staff or ALMA tools) in the generation of a Scheduling Block (SB) and identified after it is submitted to the observing queue. Consultation with the PI, if required, will be handled via the respective ARC for support. Any time spent executing such erroneous SBs will not be charged against the PI observing time.
• To implement technical changes that are initiated and required by the Observatory during Phase 2 (e.g. changes to observing strategies for a particular observing mode, to increase observing efficiency, or to calibrations needed to reach stated science goals).
• To implement minor changes as listed in Appendix B of the ALMA User Policies. Minor changes do not change the project scientific scope, increase the observing time, or require a duplication check and can be implemented by ARC staff directly.
During the time the change request is under consideration, the affected project will be immediately removed from the observing queue until the change request status is resolved.
The following changes are not allowed:
• Changes leading to duplications against ALMA proposals in the observing queue or archival observations.
• Changes that ask for capabilities that are not offered; changes must conform to the advertised capabilities and be technically feasible.
• Changes that modify the scientific objectives of the proposal, except as a result of the Proposal Review Process (e.g. a reduction in scope).
• Changes that increase the total estimated observing time for project execution.
Major changes whose main motivation is to increase the observing window of an SB, for example by changing the angular resolution or configuration, are not typically accepted. Changes to a Science Goal containing SBs whose observations have already started are strongly discouraged.
The Observatory’s decision on the requested change will be communicated to the PI via the Helpdesk. Approved changes will be implemented by ARC staff in consultation with the PI.