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http://hdl.handle.net/2289/3970
Title: | Supermassive black hole formation at high redshifts through a primordial magnetic field |
Authors: | Sethi, S.K. Haiman, Zoltan Pandey, Kanhaiya L. |
Issue Date: | 31-Aug-2010 |
Publisher: | IOP Publishing Ltd. |
Citation: | Astronomical Journal, 2010, Vol. 721, p615 |
Abstract: | It has been proposed that primordial gas in early dark matter halos, with virial temperatures T vir gsim 104 K, can avoid fragmentation and undergo rapid collapse, possibly resulting in a supermassive black hole. This requires the gas to avoid cooling and to remain at temperatures near T ~ 104 K. We show that this condition can be satisfied in the presence of a sufficiently strong primordial magnetic field, which heats the collapsing gas via ambipolar diffusion. If the field has a strength above midB mid gsim3.6 (comoving) nG, the collapsing gas is kept warm (T ~ 104 K) until it reaches the critical density n crit ≈ 103 cm-3 at which the rotovibrational states of H2 approach local thermodynamic equilibrium. H2 cooling then remains inefficient and the gas temperature stays near ~104 K, even as it continues to collapse at higher densities. The critical magnetic field strength required to permanently suppress H2 cooling is somewhat higher than the upper limit of ~2 nG from the cosmic microwave background. However, it can be realized in the rare gsim(2-3)σ regions of the spatially fluctuating B field; these regions contain a sufficient number of halos to account for z ≈ 6 quasar black holes. |
Description: | Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations) |
URI: | http://hdl.handle.net/2289/3970 |
ISSN: | 0004-637X 1538-4357 (Online) |
Alternative Location: | http://adsabs.harvard.edu/abs/2010ApJ...721..615S http://arxiv.org/abs/1005.2942 http://dx.doi.org/10.1088/0004-637X/721/1/615 |
Copyright: | 2010 IOP Publishing Limited |
Appears in Collections: | Research Papers (A&A) |
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2010_APJ_721_615.pdf Restricted Access | Restricted access | 557.22 kB | Adobe PDF | View/Open Request a copy |
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