出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present results of a high-resolution cosmological simulation which explores the process of primordial gas collapsing into a high-redshift atomic cooling halo, typically considered to be a ’first galaxy’. We consider a physically motivated scenario where a strong molecule destroying Lyman-Werner (LW) background prevents gaseous collapse, and thus star formation, in small mass halos. Only when molecular hydrogen can shield itself from LW radiation in a sufficiently massive halo will star formation be possible. We find that in a 1Mpc3 (comoving) box with a LW background corresponding to J21 = 100 collapse first occurs in a 3107M dark matter halo at z ' 12:1. A distinct phase transition occurs in the center of the halo when molecular hydrogen (H2) begins to self-shield, allowing baryons to cool, and to form a supersonically turbulent10pc core. We investigate the character of turbulence in this core, fragmentation properties, and impact on next generation star formation.
