Supermassive Dark Stars and their remnants as a possible solution to three recent cosmic dawn puzzles

TL;DR

The paper argues that Supermassive Dark Stars (SMDSs), powered by Dark Matter annihilation, can simultaneously address three cosmic dawn puzzles raised by JWST: the existence of ultra-luminous, compact Blue Monsters, the presence of overmassive black holes powering distant quasars, and the unusual nature of Little Red Dots. It develops the DS framework—from formation in minihalos with Adiabatic Contraction or DM capture, to growth via accretion, to collapse into massive black hole remnants that seed SMBHs—and links it to JWST observations, including four spectroscopically consistent SMDS candidates near $z\sim11$–$14$ and the case study of UHZ1. The work also compares SMDS seeds with Direct Collapse Black Holes, showing that SMDSs offer a more flexible heavy-seed channel and can naturally explain the observed galaxies and quasars without invoking extreme feedback suppression. It highlights testable predictions, such as characteristic low dust content, potential Helium absorption features, and possible gravitational-wave signals from DS collapse or SMBH mergers, which can be used to distinguish SMDS scenarios from alternative heavy-seed models. Overall, SMDSs provide a cohesive, testable framework that could reshape our understanding of star formation, black hole seeding, and galaxy evolution at cosmic dawn.

Abstract

The James Webb Space Telescope (JWST) has begun to revolutionize our view of the Cosmos. The discovery of Blue Monsters (i.e., ultra-compact yet very bright high-z galaxies) and the Little Red Dots (i.e., very compact dustless strong Balmer break cosmic dawn sources) pose significant challenges to pre-JWST era models of the assembly of first stars and galaxies. In addition, JWST data further strengthen the problem posed by the origin of the supermassive black holes that power the most distant quasars observed. Stars powered by Dark Matter annihilation (i.e., Dark Stars) can form out of primordial gas clouds during the cosmic dawn era and subsequently might grow via accretion and become supermassive. In this paper we argue that Supermassive Dark Stars (SMDSs) offer natural solutions to the three puzzles mentioned above.

Figures (8)

• Figure S1: Spectral Emission Distribution (SED) best fits for the SMDSs candidates presented in Table \ref{['tab:combined_properties']}. The data (blue line) and uncertainty band (shaded gray) plotted against our best fit Dark Star models (orange line). The red dashed line represents where He II$\lambda1640$ absorption feature, expected only for Dark Stars, might be observed. The normalized residuals ($\frac{F_{simul}-F_{measured}}{\sigma_{measured}}$) displayed in the lower panels of each of the SEDs show that our Supermassive Dark Star models lie consistently within 1-$\sigma$ of the NIRSpec data for each of the four objects considered. The vertical drop in the fluxes represents the Lyman break, as expected for $z\gtrsim 6$ objects due to absorption by neutral H along the line of sight Gunn-Peterson:1965. The vast majority of the other "features" in the observed spectra are actually due to noise. In the title of each plot we display the values assumed for the gravitational lensing factor ($\mu$) and the best fit values for $z_{spec}$.
• Figure S2: He II 1640 Å absorption feature identified in the spectrum of JADES-GS-z14-0 by ilie2025spectroscopicsupermassivedarkstar. Here we calculate the SNR of detection based on a polynomial fit (orange) to the observed spectrum (blue). Namely, $SNR = D_{feature}/\sigma_{cont}$, where $D_{feature}$ represents the depth of the feature below the modeled continuum, which has a scatter (noise) quantified by $\sigma$. The location of He II line is shown in black, and the size of the feature is shaded in gray. The feature is below the continuum beyond the level of noise. Estimated $SNR\simeq2.31$.
• Figure S3: Absorption features identified in the spectrum of JADES-GS-z13-0 . Left panel: He II 1440 Å Estimated $SNR\simeq2.2$. Right panel: He II 2511 Å. Esimated $NSR\simeq 4.6$.
• Figure S4: BHs with masses between $10^4$ and $10^5 M_{\odot}$, generated at $z\simeq 25$ and growing at the Eddington rate (tan shaded band), can explain the mass of UHZ1 (Solid black line) and the three previously known highest redshift quasars (denoted by diamond symbols at $z\sim 7.5$). A radiative efficiency of the accretion process $\eta= 0.114$ is needed to reproduce the growth curves from Fig. 4 of Bogdan:2023UHZ1 (shaded tan band in this figure).
• Figure S5: SMBHs of: UHZ1, J0313–1806, J1342+0928, and J1007+2115 seeded by Dark Stars. The DSs is forming at $z_{form}$ and grows via accretion at a constant rate until it collapses to a BH at a redshift labeled by $z_{BH}$. The Dark Star phase is depicted by the shaded blue region to the right of the vertical dashed line at $z=z_{BH}$. The emerging BH is assumed to grow at the Eddington accretion limit (blue-shaded region to the left of $z=z_{BH}$). To be concrete we chose $z_{form}=20$, $z_{BH}=15$, and the DS mass accretion rate ranging in the conservative range $c\in[10^{-3},10^{-2}]M_{\odot}\mathrm{yr}^{-1}$.