JWST Preparation of the PDF Attachment

This page describes the sections required to be present in the PDF attachment. This attachment is written as a standalone file using STScI provided templates, and is uploaded through APT.

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Science Justification Templates

Templates for JWST Cycle 3 Proposal PDF attachments:

Note: The templates have intentionally different margins, to accommodate about the same amount of text per page.

Proposers are encouraged to follow the JWST Proposal Checklist in planning and submitting their proposals. Proposers should also be familiar with the policies on data rights, duplications, dual-anonymous review, and other important topics covered in JWST General Science Policies.

A proposal consists of a completed APT proposal form and an attached PDF file. Template files (above) are available in several popular word-processing environments for the creation of the PDF file. Your PDF Attachment should obey the page limits given in the JWST Guidelines and Checklist for Proposal Preparation.

The entire PDF attachment must be anonymized, in accordance with the guidelines specified in JWST Anonymous Proposal Reviews.



Scientific Justification

This section should present a balanced discussion of background information, the program's goals, its significance to astronomy in general, and its importance to for the specific sub-field of astronomy it addresses. The members of the review panels will span a broad range of astronomy expertise, so one should write this section for this more general audience (i.e. not only for researchers in the corresponding sub-field).

Depending on the type of proposal, the following items should also be included:

  • Treasury GO, Legacy AR, and Pure Parallel proposals should address the value to the astronomical community of the data products that will be generated by the program.
  • Survey proposals should provide a complete description of the target sample.
  • AR proposals should describe how the project improves upon or adds to the previous use of data.
  • Theory proposals should include a description of the scientific investigations that will be enabled by the successful completion of the program, and their relevance to JWST.
  • Calibration proposals should describe what science will be enabled by the successful completion of the program, and how the currently supported core capabilities, their calibrations, and the existing data processing are insufficient to meet the requirements of this type of science.
  • Community Data Science Software Proposals should describe how the software packages that will be developed are relevant to and necessary for the reduction or interpretation of JWST data.



Technical Justification

(This item is required for GO and Survey proposals)

Describe the overall experimental design of the program, justifying the selection of instruments, modes, exposure times, and requirements. Describe how the observations contribute to the goals described in the scientific justification. Quantitative estimates must be provided of the accuracy required to achieve key science goals. The JWST ETC generally provides sufficient information to determine the necessary exposure time. For modes that require target acquisition, proposers should verify that the exposure specifications provided meet the stated criteria for success. Successful target acquisitions are crucial for the success of the specified observations, and must be verified. The description should also include the following:

  1. Special Observational Requirements (if any): Justify any special scheduling requirements, including time-critical observations. Target of Opportunity observations should estimate the probability of occurrence during Cycle 3, specify whether long-term status is requested, identify whether ToOs are disruptive or non-disruptive, and state clearly how soon JWST must begin observing after the formal activation. 
  2. Justification of Coordinated Parallels (if any): Proposals that include coordinated parallel observations should provide a scientific justification for and description of the parallel observations. It should be clearly indicated whether the parallel observations are essential to the interpretation of the primary observations or the science program as a whole, or whether they address partly or completely unrelated issues. The parallel observations are subject to scientific review, and can be rejected even if the primary observations are approved. 
  3. Justification of Duplications (if any): as detailed in the JWST Grant Funding and Budget Submissions and the JWST Duplicate Observations Policy. Any duplicate observations must be explicitly justified.


Special Requirements (if any)

(This item is required for GO and Survey proposals)

All visit-level and exposure-level special requirements must be itemized in the proposal and have a scientific justification, discussed explicitly in the PDF portion of their proposal. Special requirements may only added under exceptional circumstances after a proposal is accepted for execution. Special requirements include:

  • For Target-of-Opportunity (ToO) observations, estimate the probability of occurrence during Cycle 3, specify whether long-term status is requested, identify whether the ToOs are disruptive or non-disruptive, and clearly state how soon JWST must begin observing after formal activation.
  • Specific dates or ranges of specific dates for time-constrained observations;
  • Coordinated Parallel observations.
  • Willingness to waive exclusive access rights, either wholly or partially;
  • Requests for non-zero exclusive access periods for Large or Treasury programs;
  • Links between observations, including non-interruptible sequences;
  • Requests for low background or background-limited observations; and
  • Requests for High-End Computing time on NASA facilities.



Justify Coordinated Observations (if any)

(This item is required only for GO Proposals)

If you have plans for conducting coordinated observations with other facilities that affect the JWST scheduling, please describe them here (examples are coordinated or simultaneous observations with other spacecraft or ground-based observatories). Describe how those observations will affect the scheduling. Please, remember to follow dual-anonymous guidelines as in the rest of the proposals. 

If you have plans for supporting observations that do not affect JWST scheduling, then do not describe them here. If they improve your science case, then describe them in the "Scientific Justification" section of the proposal.

Joint JWST-ALMA Observations

Proposers requesting joint JWST-ALMA observations must provide a full and comprehensive technical justification for the ALMA portion of their program, including:

  • the choice of array (12 m, 7 m, or Total Power) and the array configuration (if the 12 m Array is requested),
  • the number of sources and the mapping area (Single Pointing, Multiple Pointings, Rectangular Mosaic of given area),
  • the requested time including overheads calculated using the Observing Tool (OT). If the requested time was not calculated using the OT, then the proposal should include an explanation for how the time was estimated,
  • the requested Band(s) and Correlator Configurations,
  • the representative sensitivity for reference array (i.e. 12m, or 7m for ACA stand-alone projects) and aggregated bandwidth used for sensitivity calculation,
  • the highest spectral and imaging signal-to-noise ratios expected in your sample,
  • any time constraints, including simultaneous or coordinated observations involving multiple observatories,
  • whether full-polarization is required. If so, then provide the coordinates of any source with a declination north of +30deg and the expected source linear/circular polarization fraction.
  • any other requirement that would be included in the OT (extra text boxes in the technical justification section).

During proposal preparation, proposers must use the ALMA Observing Tool to validate their program. In addition, they must provide a list of OT messages:

  • This must include any blue message reported by OT at the top of the Technical Justification section and any warning/error message when validating the project:
  • (Exclude obvious errors, like missing title/abstract/scientific justification, which are not required for the purpose of technical justification)

If the observing capabilities requested are not supported by the Observing Tool, then proposers must use other tools provided by ALMA (https://almascience.org/tools) and include a detailed explanation of the assumptions made and the process by which observing time was estimated. 

Upon acceptance of a Joint Proposal by STScI, PIs will be required to submit their programs to the JAO using the ALMA Observing Tool. The JAO will prepare Scheduling Blocks and perform a final detailed technical assessment. Programs with significant technical issues may be rejected at the discretion of the JAO. Once the Scheduling Blocks have been prepared, projects will immediately enter the ALMA observing queue, unless requesting observing capabilities only offered in the upcoming Cycle. In that case the project will enter the queue at the corresponding Cycle start date. Approved programs may remain in the ALMA queue for a period of up to two years.

Joint JWST-Chandra Observations

Proposers requesting joint JWST-Chandra observations must provide a full and comprehensive technical justification for the Chandra portion of their program. This justification must include:

  • the choice of instrument (and grating, if used),
  • the requested exposure time, justification for the exposure time, target count rate(s) and assumptions made in its determination,
  • information on whether the observations are time-critical; indicate whether the observations must be coordinated in a way that affects the scheduling (of either Chandra or JWST observations),
  • the exposure mode and chip selection (ACIS) or instrument configuration (HRC),
  • information about nearby bright sources that may lie in the field of view,
  • a demonstration that telemetry limits will not be violated,
  • a description of how pile-up effects will be minimized (ACIS only).

Due to increasingly challenging thermal constraints, the amount of Chandra exposure time available for High Ecliptic Latitude (HEL) targets with |bGal| > 55 deg is extremely limited.  Refer to section on HEL targets in the Chandra Proposers’ Observatory Guide for detailed information. If you request joint time on Chandra, please avoid long exposures on such targets if at all possible. You must note explicitly the requested amount of Chandra HEL time in the body of your science justification.   

Similarly, constraints that may limit the number of days your targets are observable can be difficult to accommodate within Chandra scheduling.  Chandra calculates this difficulty as Resource Cost (RC).  Refer to Section on Resource Cost in the Chandra Proposers’ Observatory Guide for detailed information. Only a fixed total number of RC points, as calculated by Chandra’s RC calculator, may be awarded by Chandra's joint partner observatories.  Every proposal requesting joint Chandra time should explicitly list the RC total of their requested Chandra time in the body of the science justification, except for ToOs where the sky position is unknown. Additionally, the proposers must verify that Chandra will be able to acquire suitable star fields for a given target using the Star Checker tool (https://cxc.cfa.harvard.edu/toolkit/starchecker.jsp). 

Technical documentation about Chandra is available from the Chandra X-ray Center (CXC) webpage, which also provides access to the Chandra Help Desk. The primary document is the Proposer’s Observatory Guide, available from the Chandra Proposal Information webpage. Full specification of approved observations will be requested during the Chandra Cycle 25 period when detailed feasibility checks will be made.

Proposers requesting joint JWST-Chandra observations must specify in the "Team Expertise" section whether they were awarded Chandra time in a previous Chandra cycle for similar or related observations.

Joint JWST-HST Observations

Proposers requesting joint JWST-HST observations must provide a full and comprehensive technical justification for the HST portion of their program, including

  • the choice of HST instrument and mode,
  • the requested exposure time, justification for the exposure time, target count rate(s), and assumptions made in their determination,
  • information on whether the observations are time-critical; indicate whether the observations must be coordinated in a way that affects the scheduling (of either HST or JWST observations),
  • any other Special Requirements, if necessary.

Technical documentation about HST is available online.

Joint JWST-NASA Keck Observations

Proposers requesting joint JWST-NASA Keck observations must provide a full and comprehensive scientific and technical justification for the NASA Keck portion of their program, including:

  • the telescope(s), instrument(s), mode(s), and wavelengths on which time is requested,
  • the requested integration time per telescope/instrument, sensitivity, and source of this information,
  • a specification of the number of nights for each semester during which time will be required, a breakdown into dark, grey, and bright time, and an explanation of how the required exposure time was estimated,
  • information on whether the observations are time-critical, and whether the observations must be coordinated in a way that affects the scheduling (of either the NASA Keck or the JWST observations),
  • a description of any special scheduling or implementation requirements (e.g., optimum and acceptable dates).
  • the results of the Keck Observatory Archive (KOA) data check. If appropriate archival Keck data exist in the KOA, proposers must provide clear scientific and technical justification for any new Keck observations of previously observed targets. 


Successful proposers for joint JWST-NASA Keck time will be notified in late February 2024 and will then be required to submit a 2024B WMKO coversheet in support of their proposal.  If you are requesting NASA Keck observations that can only be conducted in July 2024 to coincide with the start of the JWST observing cycle, you must also submit a 2024A WMKO coversheet before the Cycle 3 proposal deadline in October 2023.  The program title and abstract on the WMKO coversheet must be the same as was submitted in your Cycle 3 JWST proposal and choose “JWST Joint Program” as the allocating institution so that the WMKO proposal ID starts with a "J". It is a WMKO requirement that first-time users of an instrument have at least one lead observer present at Keck for the initial observing run.  Questions related to NASA Keck time specifically may be addressed to keckcfp@ipac.caltech.edu.

Joint JWST-NOIRLab Observations

The Joint JWST-NOIRLab time is intended to provide investigators with complementary ground-based observations that are necessary in support of their JWST programs.  Successful JWST Cycle 3 poposers will receive NOIRLab time in semesters 2024B and 2025A, due to scheduling constraints.  Proposers requesting joint JWST-NOIRLab observations must provide a full and comprehensive scientific and technical justification for the NOIRLab portion of their program, including:

  • the telescope(s) and instrument(s) on which time is requested,
  • the requested observing time per telescope/instrument, a specification of the number of nights for each semester during which time will be required, a breakdown into dark, grey and bright time, and an explanation of how the required exposure time was estimated, including information on filters, gratings, and observing conditions,
  • information on whether the observations are time-critical, and whether the observations must be coordinated in a way that affects the scheduling (of either the NOIRLab or the JWST observations),
  • a description of any special scheduling or implementation requirements (e.g., optimum and acceptable dates).

In addition to the JWST proposal, this information must be included in a NOIRLab Phase I proposal submitted through the standard NOIRLab process by the nominal April 1, 2024 deadline for semester 2024B. For Gemini proposals, a Gemini PIT proposal must be submitted. For all other telescopes, the standard NOIRLab Time Allocation proposal form must be submitted. Detailed information for Gemini and other telescopes can be found in the Call for Proposals for the 2024B semester. Proposals not received by the April 1, 2024 deadline may not be scheduled for NOIRLab time.

Successful proposers who receive time on Gemini Observatory will have to prepare a Phase II proposal which includes a more detailed description of each observation. Phase II submission instructions will be forthcoming following notification of the results of the JWST review.

Technical documentation about the NOIRLab facilities is available from the NOIRLab webpage. Questions may be directed to the NOIRLab Proposal Help Desk by e-mail to proposal-help@noirlab.edu. NOIRLab will perform feasibility checks on any approved proposals.

Joint JWST-NRAO Observations

Proposers requesting joint JWST/NRAO observations must provide a full and comprehensive technical justification for the NRAO portion of their program, including

  • the choice of NRAO telescope(s) (VLA, VLBA and/or GBT), and
  • the total estimated NRAO observing time in hours.

For Cycle3, NRAO plans to make available up to 5% of VLA, VLBA, or GBT observing time per year, to be implemented in Cycles 24B and 25A. A VLA configuration schedule is published at:

Detailed technical information concerning the NRAO telescopes can be found at:

For the VLA, joint proposals may only use capabilities defined as “general observing” in the NRAO VLA 2024B Call for Proposals, to be released in January 2024. Technical questions about proposing or observing for NRAO telescopes (whose answers are not found in the above links) should be posted to the NRAO helpdesk.

If approved for NRAO time, successful PIs will be contacted by the NRAO Scheduling Officers (schedsoc@nrao.edu for the VLA/VLBA and gbtime@nrao.edu for the GBT). The successful PIs for GBT projects will be responsible for organizing the project's information in the GBT Dynamic Scheduling Software and for carrying out their GBT observations. For the VLA and VLBA, the PIs will be responsible for submitting scheduling blocks to the telescopes' dynamic queues. Projects requiring simultaneous JWST-NRAO observations will be performed on fixed dates. In conjunction with JWST, the NRAO Scheduling Officers will inform the PIs of those dates and times, and the PIs will be responsible for submitting scheduling blocks two weeks prior to the observations.

Joint JWST-XMM-Newton Observations

Proposers requesting joint JWST/XMM-Newton observations must provide a full and comprehensive technical justification for the XMM-Newton portion of their program, including

  • the choice of prime instrument,
  • the requested exposure time, justification for the exposure time, target count rates, and assumptions made in their determination,
  • information on whether the observations are time-critical.

Technical documentation about XMM-Newton is available from the XMM-Newton webpage.



Justify Duplications (if any)

(This item is required only for GO Proposals)

Justify, on a target-by-target basis, any potential duplication with previously accepted observing programs. Use the "Duplication" checkbox in the Observation Summary to identify the duplicating observations. See JWST Data Rights and Duplications for policies on duplications.



Analysis Plan 

(This item is required for all AR proposals, including GO programs with the Archival flag set, and all Calibration proposals, including Theory) 

All AR proposals (including Theory) and all Calibration proposals (both GO and AR) should provide a detailed data analysis plan and describe the datasets that will be analyzed. The plan should include a brief summary of the likely scale of the proposed program, including the number of personnel and associated work effort while still following the JWST Anonymous Proposal Reviews. Inclusion of a target list is not required. Observing proposals that involve complex data analysis should include discussion of the analysis plan as part of the Technical Justification. AR funding becomes available within 30 days of receipt of the grant PI notification letter. Any AR programs requesting a delay in the start date for funding must provide a justification as part of the Analysis Plan and the delay must be approved by the STScI Director.

Legacy AR Proposals should also discuss the data products that will be made available to the community, the method of dissemination, and a realistic timeline. It is a requirement that data products be delivered to STScI in suitable digital formats for further dissemination via the MAST Data Archive or related channels. Any required technical support from STScI and associated costs should be described in detail.

Theory AR Proposals should discuss the types of JWST data that will benefit from the proposed investigation, and references to specific data sets in the MAST Data Archive should be given where possible. They should also describe how the results of the theoretical investigation will be made available to the astronomical community, and on what timescale the results are expected.

Calibration Proposals should discuss what documentation, and data products and/or software will be made available to STScI to support future observing programs. Proposers should explain how their programs complement ongoing calibration efforts by the STScI instrument groups. They should contact the relevant instrument groups to ensure that efforts are not duplicated, and if they are, justify why the duplications are necessary.

During the budget review process, the Financial Review Committee will compare the requested costs with the commensurate work outlined in the Analysis Plan. Support for resources outside the original scope of work will not be considered.


Proposers are reminded that the review panels will include observational and theoretical astronomers and planetary scientists with a broad range of scientific expertise. They will not necessarily have specialists in all areas of astrophysics so the proposals must be written for this  general audiences of scientists.

For a checklist of items to complete when writing your JWST proposal, see the JWST Proposal Checklist.


Next: Proposal Implementation and Execution




Notable updates


Originally published