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Galaxy Formation
When and how do the earliest galaxies first emerge from the cosmic dark ages, and what governs their star formation?
A community effort to make the scientific case for a very large JWST program on the onset of galaxy formation, and the detailed physics driving galaxy evolution.
Co-signing takes minutes. Writing a companion white paper is optional.
The Vision
Two of JWST's key science goals are to identify the first light in the Universe and to understand how the first galaxies assembled into the mature systems we see today. After five years of observations, JWST has shown that galaxies grow surprisingly luminous, massive, and chemically enriched remarkably early, mirrored by the apparently early formation and rapid growth of supermassive black holes and massive galaxies. Yet several key questions remain unanswered, leaving these goals unfulfilled.
The questions we seek to answer together mark the genesis of our own Milky Way, and of the conditions that made life possible.
The Open Questions
Only JWST can answer them, but doing so requires an ambitious survey: ultradeep imaging to discover the earliest and lowest-mass galaxies, and medium-resolution spectroscopy to measure their physical properties, characterize black holes, and confirm redshifts — in statistically robust, uniformly selected samples.
When and how do the earliest galaxies first emerge from the cosmic dark ages, and what governs their star formation?
Can we identify primordial Population III stars — during their lives, or in their explosive deaths?
When and how do the first massive black holes form, and how are they connected to the mysterious Little Red Dots?
When do the scaling relations that encode the physics regulating galaxy evolution first come into place, and how do they evolve across the first few billion years?
The Program
These goals can only be achieved through a coordinated, ambitious very-large program — one requiring up to 10% of JWST's annual allocation over multiple cycles, well beyond what the standard time allocation process can accommodate. Such a program could take many shapes, but will undoubtedly include very deep imaging and an extremely large spectroscopic sample.
The resulting dataset would become a lasting archival legacy for the entire extragalactic community, long after JWST's operational lifetime — with a generational impact approaching or surpassing that of the Sloan Digital Sky Survey.
Historically, space telescopes have accommodated such efforts through Director's Discretionary Time or Multi-Cycle Treasury programs. Inspired by the exoplanet community's unified push that yielded the Rocky Worlds DDT, we aim for the galaxy-formation community to come together in the same way.
How the Initiative Works
Our goal is a unified, broadly endorsed foundational white paper making the scientific case — supported by companion papers covering the full breadth of relevant science — to convince STScI to develop an extensive galaxy-evolution-focused DDT program.
A group of Community Representatives — a strategic cross-section of the international community — has been selected to draft an initial foundational white paper, each gathering input from their broader collaborations and institutions.
Once a draft exists, all members of the community are invited to comment on and co-sign the foundational paper.
Any co-signer may lead a companion paper on a specific science case or technical detail — each linked to the initiative to strengthen the collective case.
We maintain a public list of planned papers, host regular telecons, and provide shared title branding and templates for a unified front to STScI.
* Steering Committee
We hope the entire galaxy formation community will add their name in support of this effort. We also hope to mobilize colleagues to write companion white papers on the science they are already motivated to pursue — optional contributions that will help us realize our goal of a community-driven very large JWST program that addresses our field's highest priorities.