About this Article

STScI recently completed the proposal review and time allocation process for JWST Cycle 3, which is scheduled to begin July 1, 2024. The Cycle 3 proposal deadline revealed a very high demand for JWST observations because the scientific community is excited about the observatory performance and the ways in which JWST is expected to revolutionize astronomy. Indeed, so many proposals were submitted at the October 26, 2023 deadline that the workload for panelists serving on the Telescope Allocation Committee (TAC) was very high, straining the traditional process that STScI uses to review observing and archival proposals. For Cycle 4, STScI is planning to make minor adjustments to the Call for Proposals (described at a high level below) to enable panelists to provide the best possible proposal reviews.

Proposal Submissions and Time Allocation Committee (TAC) Planning

The JWST Science Policies Group (SPG) anticipated that the Cycle 3 Call for Proposals would be popular based on the record-breaking number of proposals submitted for Cycle 2 and the continued excellent performance of the observatory. We planned the review process assuming that there would be ~1,800 proposals submitted (~12.5% more than submitted in response to the Cycle 2 Call.) Indeed, STScI received an astounding 1,931 proposals, a record number of proposals submitted to any observatory in response to any call for proposals! Of the submitted proposals, 17 were disqualified for failing duplication checks or anonymity violations. This left a total of 1,913 proposals reviewed: 1,743 in the General Observer category, 35 in the Survey category, and 135 in the Archival Research category, requesting a total of 48,320 hours. These proposals included investigators from 47 US states (plus the District of Columbia), and investigators from 57 countries.

The Review Process

Selection of an annual JWST science program is an enormous community endeavor with participation from astronomers from all over the world. The JWST Cycle 3 TAC was the largest that STScI has ever assembled, including more than 600 reviewers (~25% more reviewers than the Cycle 2 TAC). Thanks to everyone who participated in the review, including our outstanding TAC Chair (Emily Levesque), 16 Panel Chairs, 3 At-Large Members, 163 Discussion Panelists, 251 External Panelists, and 200 Expert reviewers (see Table 4 for the list of JWST TAC Discussion Panelists). Expert reviewers provide additional reviews for proposals that are reviewed by the Executive Committee (EC) and Joint observatory proposals. STScI anticipates that the SPG will need to continue to recruit large numbers of community members to review the very large number of JWST proposals. If you are interested in serving as a reviewer, please volunteer!

The Cycle 3 TAC met during the last week of January and the first week of February. The topical discussion panels met online January 29 – February 2 to discuss and rank the larger small (15 – 25 hour), medium, archival, and survey proposals. The Executive Committee composed of the TAC Chair, Panel Chairs, and At-Large Members met in person February 5 – 7 to discuss the Large, Treasury, and Archival Legacy proposals. The Panel Chairs did an outstanding job organizing the schedules for their topical discussion panels, enabling reviewers to attend to both professional and personal responsibilities during meeting days. The Executive Committee reviewed a total of 104 Large, Treasury, and Archival Legacy proposals, an unusually large number of proposals, across all areas of astrophysics from Solar System to Large Scale Structure science. To better balance the work among the External Panelists, Discussion Panelists, and the Executive Committee members, STScI is examining the hour boundaries between Very Small and Small, Small and Medium, and Medium and Large proposals and dividing the Executive Committee into a Galactic and an Extragalactic Executive Committee with the help of the JSTUC.

The Science Program

The recommendations from the Cycle 3 TAC were presented to the STScI Director for endorsement on February 22, 2024. Table 1 summarizes the main results: 253 proposals were accepted for implementation, including 213 observing proposals, 3 survey proposals, and 37 archival research and theory programs. Some 5,500 hours were allocated with a relatively flat success rate by proposal size (Fig. 1). Approximately 33.8% of the proposals are led by PIs from ESA countries, and 4.2% by PIs from Canada. Table 2 shows the overall PI distribution by country. In total, there are 2,097 unique investigators on the accepted programs. Half of the successful PIs were first-time PIs on a HST or JWST proposal. Student PIs led 12% of the successful proposals. The accepted observing programs include representation from all major observing instrumental observing modes (Table 3). As in Cycles 1 and 2, approximately 75% of the observing time on JWST will be devoted to spectroscopic programs. A full summary of the acceptance statistics is posted on the JSTUC webpage (Cycle 3 GO/AR Results).

The accepted programs span the full range of science anticipated for JWST. Figure 2 shows the proportional distribution by science category.

The Large, Treasury, and Archival Legacy programs selected by the Executive Committee spanned a wide range of astrophysics, from Exoplanets and Exoplanet Formation, Stellar Physics and Stellar Types, and Stellar Populations and the ISM to Galaxies, Supermassive Black Holes and Active Galaxies, and Large Scale Structure of the Universe. For Exoplanets and Exoplanet Formation, five programs were selected: (1) KRONOS will investigate the C, N, O, and S abundances of seven, young sub-Neptune atmospheres (<200 Myr); (2) “Using stellar contamination proxy TRAPPIST-1b to search for an atmosphere on TRAPPIST-1 e” will search for an atmosphere of a terrestrial planet in the habitable zone; (3) “JWST’s Exoplanet Grand Tour Spectroscopic Survey” will provide a comprehensive HST and JWST survey of exoplanetary atmospheres for planets with Neptune to Jupiter sizes building on previous JWST observations; (4) “Into the Spotlight: Unveiling Wide-Separation Sub-Jupiters for Future JWST Characterization” will survey young stars in the β Pictoris Moving group for sub-Jupiter and sub-Saturn mass exoplanets at separations beyond 10 au; and (5) “Eyes on the Stars: A JWST Population Survey of Exoplanet Host Star Heterogeneities and Spectral Contributions to Transits” will analyze archival observations of 21 transiting exoplanet systems to better understand the properties of host stars and their impact on transit observations. Venturing further into the Milky Way, HEFE will study low mass star formation in an 8 pc long, massive filament within Orion Nebula OMC2/3 region, containing 46 protostars.

Among the extragalactic programs, “SKY in 30D” will compare ERO observations of 30 Doradus, the brightest starburst galaxy in the Local Group, with existing Hubble archival data to measure the kinematics of 0.8 – 17 M_sun stars. COSMOS-3D will obtain NIRCam/WFSS and deep MIRI parallel imaging within the COMOS-Webb field to measure the redshifts of ~20,000 galaxies and 5,000 AGN, including >4,000 galaxies and up to 500 AGN in the Epoch of Reionization. CAPERS will obtain deep NIRSpec prism observations of the EGS, COSMOS and UDS fields to measure redshifts for 10,000 galaxies, including 2,000 galaxies at 4 < z < 9.5 and 100 z > 9.5 galaxies identified in CEERS and PRIMER. “Galaxy mass build-up in the early universe” will obtain deep MIRI F770W and F1000W imaging of the Hubble UDF to complement existing NIRCam, NIRSpec, and MIRI F560W surveys. DARK-SKY will constrain the Zodiacal Light and Diffuse Extragalactic Background Light using archival observations. Finally, two pure-parallel surveys using NIRCam/WFSS were approved: (1) SAPPHIRES, a wide-field, spectroscopy-based census of luminous galaxies at z = 4-9 and beyond. (2) POPPIES, a wide-field, blind, emission line survey to identify galaxies at z > 7, quantify the evolution of Broad Line AGN, investigate the evolution of the mass-metallicity relation in low mass galaxies, measure galaxy star formation rates, and identify 15-20 late-M, L, and T dwarfs in the Milky Way.

Dual Anonymous Peer Review Warning

The SPG reminds proposers that submitted proposals should not include clearly identifiable references to work carried out by proposal teams. Specifically, the SPG saw two kinds of Dual Anonymous Peer Review (DAPR) violations that were new: (1) A handful of successful Cycle 2 Survey and Target of Opportunity proposals were resubmitted to the Cycle 3 TAC with the same titles and abstracts. The names of PIs, Co-PIs, and CoIs are publicly available for all approved programs. Unlike ground-based observatories, STScI does not provide an advantage to programs that were approved in a previous cycle but not executed. Recycling titles and abstracts presents a difficulty because panelists are able to trivially identify proposal teams when trying to place submitted proposals into the context of already approved programs. (2) In addition, a couple of proposals had titles and text lifted from publicly available white papers, referenced in the text, that also made identification of proposal teams straight-forward.

Cycle 4

The JWST Cycle 4 proposal deadline is coming up fast. With such a high oversubscription rate, there were unfortunately many excellent proposals that were not selected in Cycle 3. We hope that these proposals will be submitted in response to the Cycle 4 Call for Proposals. The Cycle 4 Call for Proposals will be issued August 1, 2024, with a proposal deadline of Wednesday, October 16, 2024.

The SPG is working on three changes to the cycle 4 Call for Proposals:

1. Reducing the page limits for proposals – The JSTUC noted that the work load for TAC reviewers was very high, STScI’s proposal page limits are substantially more generous than other ground and space-based observatories. Science Justifications were often repetitive. We anticipate that the page limits for Small proposals will decrease from 8 pages to 4 pages and those for Large proposals from 12 pages to 6 pages.
2. Adjusting the boundaries between size categories – The SPG plans to better balance the workload among the External Panelists, Discussion Panelists, and the Executive Committee. For example, the boundary between Very Small and Small proposals will increase from 15 hours to 20 hours; the boundary between Small and Medium proposals will increase from 25 to 50 hours; and the boundary between Medium and Large proposals will increase from 75 hours to 130 hours.
3. Adjusting the science categories – The SPG plans to better group science keywords within science categories to better reflect scientific communities. For example, the science keywords in Stellar Physics and Stellar Populations will be regrouped into categories focusing on “Stars” and “Dust and Gas.” Exoplanets and Exoplanet Formation will be split into “Exoplanet Atmospheres and Habitability” and “Planetary System Formation.”

The SPG plans to publish another STScI Newsletter Article before the Cycle 4 Call is issued with more details to help proposers navigate the changes. Proposers should also read the Call for Proposals carefully before submitting proposals.

On a personnel note, we welcome Aleksandra Hamanowicz to the JWST Science Policies Group as our new Technical Manager. We thank Brett Blacker for his many years of service supporting both Hubble and JWST, interfacing with the community and organizing the Telescope Allocation process. JWST Cycle 3 was the last proposal review for which Brett served as the Technical Manager.

Acknowledgements

We are extremely grateful to everyone who was involved in this process at any stage. It takes an enormous amount of time and energy from a huge number of people to support the review from start to finish.

We thank the JWST TAC Chair, the Panel Chairs, the At-Large members, panel members and external reviewers for the extensive efforts that they all invested in service on the Cycle 3 TAC.

In addition, numerous STScI personnel supported the review. The overall logistics were coordinated by the TAC Managers, Christine Chen and Katey Alatalo, with extensive support from Brett Blacker and Aleksandra Hamanowicz, and from Sherita Hanna in the Events Planning Group. Among others involved were:

The JWST Cycle 3 Telescope Allocation Committee, comprising more than 180 astronomers from around the world, met at the end of January through the beginning of February. Sixteen Discussion Panels met virtually the week of 1/29-2/2/2024. The Executive Committee met in person at the Institute 2/5-7/2024. Apart from some very minor glitches, everything ran remarkably smoothly. We received numerous verbal comments and e-mails from panelists and NASA officials who greatly appreciated the professionalism and help shown by all the Institute staff.

The TAC logistics were devised and coordinated by Brett Blacker and Alex Hamanowicz. Among the others involved in making the process a success were, in no particular order:

Administrative Support: Melody Easton, Sherita Hanna, Holly Reedy (ESA), Shemiah Smith, Darlene Spencer

WASABI Support: Maria Bertch, Jeff Bucklew, Alex Framerini, Craig Hollinshead, Lauretta Nagel, Doug Paul

Panel Support Staff:  Gagandeep Anand, Nicole Arulanantham, Paul, Bennet, Sarah Betti, Calum Hawcroft, Amy Jones, Logan Jones, Intae Jung, Aiden Kovacs, Valentina Melgarejo, Shelley Meyett, Sapna Mishra, Anna Payne, Justin Pierel, Sarah Steiger, Elizabeth Tarantino, Brittany Vanderhoof

Science Policies: Katey Alatalo, Alessandra Aloisi, Amber Armstrong, Brett Blacker, Christine Chen, Andy Fruchter, Aleksandra Hamanowicz, Susan Kassin, Claus Leitherer, Crystal Mannfolk, Amaya Moro Martin, Neill Reid, Jamila Pegues, Elena Sabbi, Linda Smith, Laura Watkins

Instruments & Telescope Support: Dave Golimowski, Bryan Hilbert, Diane Karakla, Stephanie LaMassa, Katie Murray, Alberto Noriega Crespo, Patrick Ogle, Deepashri Thatte

Scheduling: Beth Perriello, Tony Roman

JWST Mission Office Observers: Stacey Bright, Macarena Garcia-Marin, Massimo Stiavelli, Jeff Valenti

ESA Observers: Chris Evans, Paule Sonnetrucker

Facilities: Mike Venturella, Tiffany Lallo, Raven Baxter, Andre DeShazo, Gee, Bermond Few, Rob Franklin

Tech Support: Thomas Marufu, Gary Gilbert, Kevin Flinn and the whole ITSD team!

Thanks to all of you!