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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