Cosmic star-formation decline, the first galaxies and early black holes from the energy cascade of dark matter and gas
Year: 2026
Type: preprint
Abstract: Manuscript and CSV data behind the figures and tables of Xu (2026), Cosmic star-formation decline, the first galaxies and early black holes from the energy cascade of dark matter and gas, Research Square preprint, doi:10.21203/rs.3.rs-11556357/v1. Contents: the manuscript (P01_revised.pdf) and the folder csv/ with 30 CSV files holding the data behind Figs. 2 to 8, Figs. B1, Tables 1, 3, 4, 5, D1 and F1, and the numbers of Sections 2 to 5. Companion dataset: the 177 bulges of Table B1 and the black-hole masses of Xu (2025), doi:10.1093/mnras/stae2766, arXiv: arXiv:2501.07608. Major findings (Illustris-1-Dark and observed galaxies, 0 ≤ z ≤ 20): Haloes of fixed mass collapse at a fixed density contrast until a crossover at a* ≈ 0.5–0.64, after which they grow denser; the characteristic mass mh* ∝ a3θ, with θ falling from 1 to 1/2 at a*. Gas radiates its random energy; if its contrast stays fixed, the cascade rate shared by all galaxy cores rises as (1+z)5/2. The rate at the effective radius lies below the core rate by a factor F ∝ M-2/3: about 1 in spheroids and about 102 in low-mass discs. Late decline: after a*, the fraction of infalling gas that cools efficiently falls as (1+z)-5/4, steepening the local slope of the star-formation density from 1.5 to 2.7 with no added parameter. First galaxies: a sharp onset of feedback-free star formation at z ≈ 10.5 fits the JWST UV densities and luminosity functions better than bursty or feedback-free alternatives (ΔAIC ≥ 42). Black holes: the luminosity ceiling L/LEdd ∝ (1+z)2 MBH-1/5 encloses all but 24 of 1.5×105 quasars, and MBH/σ5 stays constant. JADES black-hole hosts lie higher in σ3/Re than local disc hosts measured alike, by +1.18 dex at fixed σ and +1.98 dex at fixed dynamical mass.
Author: Xu, Zhijie (Jay)
Institution: Pacific Northwest National Laboratory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225610122
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