The remnant black holes (BHs) of supermassive stars formed at z > 10 are promising candidates of the seeds for supermassive BHs. They are thought to form in pristine atomic cooling halos in which H2 cooling is totally suppressed by strong external radiation. Here, we obtain the critical FUV specific intensity Jcr21 (in units of 10-21erg s-1 Hz-1 sr-1 cm-2) required for supermassive star formation, with non-local thermodynamic equilibrium (non-LTE) primordial-gas chemistry. We consider the non-LTE chemistry with the vibrationally resolved H+2 kinetics, as well as realistic radiation spectra of galaxies. We find that while the effect of non-LTE H+2 chemistry is important for soft radiation sources, it is negligible and Jcr21 ∼ 1000 for the hard spectra of young and metal-poor galaxies, considered as typical radiation sources in the early Universe.
|Number of pages||2|
|Journal||Memorie della Societa Astronomica Italiana - Journal of the Italian Astronomical Society|
|Publication status||Published - 2017|
|Event||2017 Conference Francesco's Legacy: Star Formation in Space and Time - Firenze, Italy|
Duration: 2017 Jun 5 → 2017 Jun 9