The dawn of the first galaxies

@misc{vallini2026dawn,
  title = {{The dawn of the first galaxies}},
  author = {Livia Vallini and Tanio Diaz Santos and Belen Alcalde Pampliega and Hiddo Algera and Manuel Aravena and Cecilia Bacchini and Tom Bakx and Maruša Bradač and Leindert A. Boogaard and Karina I. Caputi and Stefano Carniani and Karin Cescon and Francoise Combes and Carla Cornil-Baïotto and Pierre Cox and Elisabete Da Cunha and Roberto Decarli and Miroslava Dessauges-Zavadsky and Andreas L. Faisst and Roman Fernandez Aranda and Andrea Ferrara and Jonathan Freundlich and Yoshinobu Fudamoto and Seiji Fujimoto and Carlotta Gruppioni and Takuya Hashimoto and Natsuki Hayatsu and Kasper E. Heintz and Jacqueline Hodge and Ryota Ikeda and Gareth C. Jones and Mahsa Kohandel and Adarsh Kumar and Alvaro Labiano and Ivanna Langan and Andrea Lapi and Umberto Maio and Marcella Massardi and Dieu D. Nguyen and Andrea Pallottini and Mamta Pandey-Pommier and Miguel Pereira-Santaella and Gergö Popping and Francesca Pozzi and Prachi Prajapati and Dominik A. Riechers and Francesca Rizzo and Lucie Rowland and Sander Schouws and Irene Shivaei and Laura Sommovigo and Yuma Sugahara and Hannah R. Stacey and Sandro Tacchella and Eros Vanzella and Enrico Veraldi and Julie Wardlow and Joris Witstok and Anita Zanella},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.20733},
  eprint = {2610.20733},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.20733},
}

TY  - UNPB
TI  - The dawn of the first galaxies
AU  - Livia Vallini
AU  - Tanio Diaz Santos
AU  - Belen Alcalde Pampliega
AU  - Hiddo Algera
AU  - Manuel Aravena
AU  - Cecilia Bacchini
AU  - Tom Bakx
AU  - Maruša Bradač
AU  - Leindert A. Boogaard
AU  - Karina I. Caputi
AU  - Stefano Carniani
AU  - Karin Cescon
AU  - Francoise Combes
AU  - Carla Cornil-Baïotto
AU  - Pierre Cox
AU  - Elisabete Da Cunha
AU  - Roberto Decarli
AU  - Miroslava Dessauges-Zavadsky
AU  - Andreas L. Faisst
AU  - Roman Fernandez Aranda
AU  - Andrea Ferrara
AU  - Jonathan Freundlich
AU  - Yoshinobu Fudamoto
AU  - Seiji Fujimoto
AU  - Carlotta Gruppioni
AU  - Takuya Hashimoto
AU  - Natsuki Hayatsu
AU  - Kasper E. Heintz
AU  - Jacqueline Hodge
AU  - Ryota Ikeda
AU  - Gareth C. Jones
AU  - Mahsa Kohandel
AU  - Adarsh Kumar
AU  - Alvaro Labiano
AU  - Ivanna Langan
AU  - Andrea Lapi
AU  - Umberto Maio
AU  - Marcella Massardi
AU  - Dieu D. Nguyen
AU  - Andrea Pallottini
AU  - Mamta Pandey-Pommier
AU  - Miguel Pereira-Santaella
AU  - Gergö Popping
AU  - Francesca Pozzi
AU  - Prachi Prajapati
AU  - Dominik A. Riechers
AU  - Francesca Rizzo
AU  - Lucie Rowland
AU  - Sander Schouws
AU  - Irene Shivaei
AU  - Laura Sommovigo
AU  - Yuma Sugahara
AU  - Hannah R. Stacey
AU  - Sandro Tacchella
AU  - Eros Vanzella
AU  - Enrico Veraldi
AU  - Julie Wardlow
AU  - Joris Witstok
AU  - Anita Zanella
PY  - 2026
DA  - 2026/10/18
PB  - arXiv
DO  - 10.48550/arxiv.2610.20733
UR  - https://arxiv.org/abs/2610.20733
AB  - Understanding how the first galaxies assembled their stellar mass at cosmic dawn is a central frontier of modern astrophysics. JWST has now revealed an unexpected population of ultraviolet-bright galaxies at z>10, whose intense emission points towards a rapid stellar mass growth that challenges current models of early galaxy assembly. Yet, the cold gas fueling this growth remains hidden: current ALMA sensitivity restricts routine detection to only the brightest ionized-gas tracers such as [OIII] 88μm, while [CII] 158μm, a key coolant and gas-mass proxy of the neutral interstellar medium (ISM), is undetected beyond z∼8. This leaves fundamental questions unanswered: how quickly primeval galaxies gathered cold gas and turned it into stars; what physical conditions (density, temperature, radiation field) characterized their ISM; how fast metals and dust built up; and how feedback regulated early gas assembly. Only a transformational sub-millimeter facility like ALMA2040 can address these questions, enabling systematic surveys of [CII] in the first galaxies and providing a representative census of gas fractions and depletion times. A simulated galaxy at z=11.3 shows that ALMA2040 not only will detect, but also spatially resolve its merging cold-gas structure in [CII] on ∼200 pc scales in 5 hours (below 100 pc in 10 hours). ALMA2040 will also spectrally resolve multiple lines simultaneously, akin to integral-field spectroscopy, providing the key diagnostics needed to break density-metallicity-radiation-field degeneracies and map the multi-phase ISM of z>10 galaxies. The combination of dramatically increased line sensitivity and wide instantaneous bandwidth will push the search for the first galaxies out to the earliest cosmic times, with [OIII] detectable up to z∼20. ALMA2040 will thus be transformative for understanding how the first galaxies assembled at cosmic dawn.
ER  -