Data Access Policy
Science data obtained from JWST will be released to the astronomical community following an exclusive access period, during which the Principal Investigating Team enjoys exclusive scientific use. The duration of the exclusive access period depends upon the program. Access to data during this period is restricted to authenticated and authorized users. Principal Investigator team members and MAST users should acknowledge the source of the data and the funding grant (if any) in any publication using JWST data. Most engineering data are not restricted, but can only be retrieved by authenticated users.
More about the data access policy
Access to and use of JWST science data is governed by a mission policy not unlike that adopted for HST. Science data obtained from JWST will be released to the astronomical community and the public following an exclusive access period. Access to archived data during this period is limited to authenticated and authorized investigators. Principal Investigator team members and MAST users should acknowledge the source of the data and the funding grant (if any) in any publication using JWST data.
Exclusive access period
JWST science data become available to the astronomical community and the public upon expiration of an exclusive access period, during which the investigator team enjoys exclusive access to these data in MAST. This period applies at the data product level (rather than to a completed observing program), and begins the moment that individual exposures obtained from the spacecraft have been calibrated and made available in MAST. The duration of the exclusive access period depends in part upon the type of observing program used to obtain the data, as summarized in the following table.
Table 1. Exclusive access period by program type
Data obtained during JWST science commissioning, possibly including ERS program exposures, may be embargoed for a limited period of time following the observation to verify the performance of the system and the data processing, or for the preparation of public outreach materials.
Principal Investigators (PIs) have the option of waiving all or part of their exclusive access period; in certain limited cases the STScI Director may grant a request for an extension. Note that all data, whether or not access is restricted within MAST, may be used by authorized JWST project staff for monitoring and diagnostic purposes. See the policy on Data Rights and Data Dissemination for details.
Access to exclusive access data in MAST requires users to establish electronic credentials with STScI; browsing and retrieval of such data requires both authentication of the user credentials and authorization to access data from particular programs.
Higher-Level Data Products
The period of exclusive access for some higher-level data products is a little more complicated. This is because some data products may be created by combining data from multiple observations that are obtained over a (possibly extended) period of time. The data that contribute to a combined product are associated, and if these associations change because new observations become contributors, the higher-level product is automatically recreated when the new observations are processed. In this case the exclusive access period is determined by the most current dataset that contributes to the associated high-level product. For more information about these cases, please refer to the associations documentation.
This means that, although some calibrated exposures that contribute to an association may be public, the higher-level product of the association will not be public if the most recent exposures within the association fall within the exclusive access period. This creates the somewhat odd possibility that certain high-level products (e.g., a stage-3 tiled image mosaic of an extended field) might revert to exclusive access, even if they were previously public. Note that stage 2c data products (see Data Product Naming Conventions) represent a special case. These calibrated exposure-level products contain data (actually, concomitant data quality values) that originate from all the science exposures that are included in the association. As such the period of exclusive access for these products will be governed by that for the most recent observation from which they were created.
JWST engineering data are also hosted at MAST, and are obtained contemporaneously with science data. Most engineering data are not restricted, and may be retrieved by any authenticated user (i.e., they must be logged in to MAST to retrieve these data).
Investigator team members who wish to access data within the exclusive access period must establish a STScI MyST account to establish electronic credentials to authenticate their identity. PIs and CoIs of JWST observing programs already have MyST credentials, which they used to submit their proposals for review. Investigator team members must also be authorized to access data from their programs. PIs will automatically receive such authorization, which they may also grant to any collaborator who is registered with the STScI MyST.
Data for which the exclusive access period has expired may be retrieved anonymously from MAST. A MyST account is not required to search, view, explore with MAST tools, or retrieve data that have been released to the public.
It is important for investigators who publish scientific results based on MAST data to acknowledge the mission and (if applicable) the source of funding. The appropriate acknowledgement depends upon which data are used. See the appropriate acknowledgement for JWST data on the MAST Mission Acknowledgements page. This page also contains acknowledgements for all other missions hosted at MAST.
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