Clumpy star-forming regions as the origin of the peculiar morphology of high-redshift galaxies

Masafumi Noguchi

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106 Citations (Scopus)


Many high-redshift galaxies have peculiar morphologies and photometric properties. It is not clear whether these peculiarities originate in galaxy- galaxy interactions (or mergers) or are intrinsic to the galaxies, a natural consequence of the star formation process in primeval systems. Here I report the results of numerical simulations of protogalaxy evolution, which show that the gas-rich disk of a young galaxy becomes gravitationally unstable and fragments into massive clumps of sub-galactic size. Most of the stars are formed in the discrete clumps, thereby providing a natural explanation for the peculiar morphology of high-redshift galaxies. The dynamical evolution of these young systems is dominated by the clumps and ultimately leads to structures resembling present-day galaxies, with a spheroidal bulge and an exponential disk. I interpret the differences between the Hubble types of galaxies as resulting from different timescales of disk formation. Finally, the model provides a causal link between the emergence of quasar activity and the dynamical evolution of the host galaxy.

Original languageEnglish
Pages (from-to)253-256
Number of pages4
Issue number6673
Publication statusPublished - 1998 Mar 19

ASJC Scopus subject areas

  • General


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