ALMA2040: Mapping the Spatially Resolved Dust and Star Formation Physics Driving High-z Galaxy Assembly

Daizhong Liu; Gergö Popping; Pierre Cox; Andreas Faisst; Mamta Pandey-Pommier; Dieu Nguyen; Román Fernandez Aranda; Elisabete da Cunha; Andrea Lapi; Tanio Díaz Santos; Ryota Ikeda; Jacqueline Hodge; Isabella Lamperti; Manuel Aravena; Irene Shivaei; Adarsh Kumar; Roberto Decarli; Mahmoud Hamed; Umberto Maio; Gareth Jones; Jianhang Chen; Sylvia Adscheid

arXiv · 2610.22228

ALMA2040: Mapping the Spatially Resolved Dust and Star Formation Physics Driving High-z Galaxy Assembly

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Abstract

Interstellar dust reprocesses approximately half of the starlight emitted across cosmic history. However, dust temperature, which is essential to convert continuum flux into dust mass, molecular gas mass, and obscured star-formation rates, remains largely unconstrained on sub-galactic scales at high redshift. While single-band ALMA imaging has characterized continuum sizes for hundreds of z>1 galaxies, single-frequency measurements cannot separate the dust mass column from the local dust heating. To date, spatially resolved (<0.5-arcsec) multi-band dust temperatures exist in the literature for only ~10 extreme systems (quasars, hyperluminous starbursts, or strongly lensed galaxies) at z>1, with ongoing programs within a few years adding at most a few dozen submillimeter or UV-bright galaxies. This still leaves typical main-sequence disks largely unexplored across cosmic history. With an anticipated ~30 times improvement in continuum sensitivity (compared to the current ALMA), simultaneous multi-band receivers, and (sub-)kpc angular resolution, ALMA2040 will transform resolved dust thermometry into a systematic survey science. Here, we present the scientific rationale and technical requirements, highlighting a future statistically meaningful survey with > 100 representative main-sequence galaxies across cosmic epochs. Realistic visibility simulations demonstrate that ALMA2040 measures radial temperature gradients with ~0.5-4 K precision (L_IR~10^{12} L_sun in 2 h on-source at z~2). These measurements will break the degeneracy between intrinsic compactness and temperature gradients, deliver the first extinction-free, temperature-calibrated resolved star-formation relations, and uniquely trace radiative feedback and disk maturation from cosmic noon to cosmic dawn.

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Daizhong Liu, Gergö Popping, Pierre Cox, Andreas Faisst, Mamta Pandey-Pommier, Dieu Nguyen, Román Fernandez Aranda, Elisabete da Cunha, Andrea Lapi, Tanio Díaz Santos, Ryota Ikeda, Jacqueline Hodge, Isabella Lamperti, Manuel Aravena, Irene Shivaei, Adarsh Kumar, Roberto Decarli, Mahmoud Hamed, Umberto Maio, Gareth Jones, Jianhang Chen, Sylvia Adscheid. 2026-10-15. ALMA2040: Mapping the Spatially Resolved Dust and Star Formation Physics Driving High-z Galaxy Assembly. https://arxiv.org/abs/2610.22228

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