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The first generation of star-forming haloes.

Reed, D.S.; Bower, R.; Frenk, C.S.; Gao, L.; Jenkins, A.; Theuns, T.; White, S.D.M.


D.S. Reed

R. Bower

L. Gao

S.D.M. White


We model gas cooling in high-resolution N-body simulations in order to investigate the formation of the first generation of stars. We follow a region of a Lambda cold dark matter (ΛCDM) universe especially selected to contain a rich cluster by the present day. The properties of the dark haloes that form in these subsolar mass-resolution simulations are presented in a companion paper by Gao et al. The first gas clouds able to cool by molecular hydrogen (H2)-line emission collapse at extremely high redshift, z ≈ 47, when the mass of the dark halo is 2.4 × 105 h−1 M⊙. By z ≈ 30, a substantial population of haloes are capable of undergoing molecular hydrogen cooling although their ability to form stars is dependent on the efficiency of feedback processes such as dissociating Lyman—Werner radiation. The mass of the main halo grows extremely rapidly and, by z ≈ 36, its virial temperature has reached 104 K, at which point gas cooling becomes dominated by more effective atomic processes. By z ≈ 30, a small ‘group’ of such potential galaxies will have formed unless prevented from doing so by feedback processes. By this redshift, massive (≳100 M⊙) Population III stars are able to ionize gas well beyond their own host halo and neighbouring H II regions can percolate to form an ionized superbubble. Such patches would be too widely separated to contribute significantly to reionization at this time. The large number density of early cooling haloes in the pre-reionized universe raises the exciting prospect that this ultra-early generation of stars may be observable as gamma-ray bursts or supernovae.


Reed, D., Bower, R., Frenk, C., Gao, L., Jenkins, A., Theuns, T., & White, S. (2005). The first generation of star-forming haloes. Monthly Notices of the Royal Astronomical Society, 363(2), 393-404.

Journal Article Type Article
Publication Date 2005-10
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 363
Issue 2
Pages 393-404
Keywords methods : N-body simulations; galaxies : formation; galaxies : haloes; cosmology : theory; dark matterPOPULATION-III STARS; DARK-MATTER HALOES; 1ST COSMOLOGICAL OBJECTS; PROBE WMAP OBSERVATIONS; PRIMORDIAL GAS; RADIATIVE FEEDBACK; MASS FUNCTION; HIGH-REDS
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