Primordial Rotating Disk Composed of geq15 Dense Star-Forming Clumps at Cosmic Dawn
Reviewed by Pithpith:VVABIWXSopen to challenge →
read the original abstract
Early galaxy formation, initiated by the dark matter and gas assembly, evolves through frequent mergers and feedback processes into dynamically hot, chaotic structures. In contrast, dynamically cold, smooth rotating disks have been observed in massive evolved galaxies merely 1.4 billion years after the Big Bang, suggesting rapid morphological and dynamical evolution in the early Universe. Probing this evolution mechanism necessitates studies of young galaxies, yet efforts have been hindered by observational limitations in both sensitivity and spatial resolution. Here we report high-resolution observations of a strongly lensed and quintuply imaged, low-luminosity, young galaxy at $z=6.072$ (dubbed the Cosmic Grapes), 930 million years after the Big Bang. Magnified by gravitational lensing, the galaxy is resolved into at least 15 individual star-forming clumps with effective radii of $r_{\rm e}\simeq$ 10--60 parsec (pc), which dominate $\simeq$ 70\% of the galaxy's total flux. The cool gas emission unveils a smooth, underlying rotating disk characterized by a high rotational-to-random motion ratio and a gravitationally unstable state (Toomre $Q \simeq$ 0.2--0.3), with high surface gas densities comparable to local dusty starbursts with $\simeq10^{3-5}$ $M_{\odot}$/pc$^{2}$. These gas properties suggest that the numerous star-forming clumps are formed through disk instabilities with weak feedback effects. The clumpiness of the Cosmic Grapes significantly exceeds that of galaxies at later epochs and the predictions from current simulations for early galaxies. Our findings shed new light on internal galaxy substructures and their relation to the underlying dynamics and feedback mechanisms at play during their early formation phases, potentially explaining the high abundance of bright galaxies observed in the early Universe and the dark matter core-cusp problem.
This paper has not been read by Pith yet.
Forward citations
Cited by 6 Pith papers
-
The Fraction of Clumpy Galaxies in JADES Over $2<z<9$
JWST data show the clumpy galaxy fraction increasing from ~10% at z~7.75 to ~70% at z~2.75 for log(M*/Msun) >=9, with mass dependence and suggested formation mechanisms differing by epoch.
-
Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of $\eta$ Carinae
LRDs are reinterpreted as intermediate-mass super-Eddington systems with wind-driven pseudo-photospheres that explain their spectra and imply engine masses below 10^5 solar masses rather than overmassive black holes.
-
On the quenching of LRD X-ray emission by both Compton-thick gas and high accretion rates
LRDs require Compton-thick gas at moderate metallicity plus high accretion rates producing weak X-rays to explain their non-detection, implying they are not chemically pristine.
-
Stellar feedback SPICEs up [C II] emission in the first galaxies
Simulations find [C II] traces star formation robustly but underestimates outflow speeds and mass-loading factors by factors of 2-5, with feedback type affecting disk settling but not distinguishable from [C II] spati...
-
Gravitational Waves from the Cosmic Dawn: Tracing Cosmic Black Hole Binaries with ET, LGWA and LISA
Super-Eddington accretion boosts predicted LISA detections of high-redshift black hole binaries to ~64 per year while dropping ET detections to ~4 per year, compared to ~32 and ~64 under Eddington-limited growth.
-
Probing the Nature of Lyman Continuum Emitting and Low-metallicity Galaxies Using the SKA
SKA-Mid is predicted to yield samples of 10-100 low-metallicity Lyman continuum emitting galaxies per square degree, enabling multi-wavelength studies of feedback processes linked to ionizing photon escape.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.