Early Structure Formation from Primordial Density Fluctuations with a Blue, Tilted Power Spectrum: High-redshift Galaxies
Abstract Recent observations by the James Webb Space Telescope (JWST) discovered unexpectedly abundant luminous galaxies at high redshift, posing possibly a severe challenge to popular galaxy formation models. We study early structure formation in a cosmological model with a blue, tilted power spect...
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Published in | The Astrophysical journal Vol. 963; no. 1; pp. 2 - 9 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Philadelphia
The American Astronomical Society
01.03.2024
IOP Publishing |
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
Recent observations by the James Webb Space Telescope (JWST) discovered unexpectedly abundant luminous galaxies at high redshift, posing possibly a severe challenge to popular galaxy formation models. We study early structure formation in a cosmological model with a blue, tilted power spectrum (BTPS) given by
P
(
k
)
∝
k
m
s
with
m
s
> 1 at small length scales. We run a set of cosmological
N
-body simulations and derive the abundance of dark matter halos and galaxies under simplified assumptions on star formation efficiency. The enhanced small-scale power allows rapid nonlinear structure formation at
z
> 7, and galaxies with stellar mass exceeding 10
10
M
⊙
can be formed by
z
= 9. Because of frequent mergers, the structure of galaxies and galaxy groups appears clumpy. The BTPS model reproduces the observed stellar mass density at
z
= 7–9, and thus eases the claimed tension between galaxy formation theory and recent JWST observations. The large-scale structure of the present-day Universe is largely unaffected by the modification of the small-scale power spectrum. We conduct a systematic study by varying the slope of the small-scale power spectrum to derive constraints on the BTPS model from a set of observations of high-redshift galaxies. |
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Bibliography: | Galaxies and Cosmology AAS51306 |
ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/ad22e0 |