open access

https://hdl.handle.net/2115/57652

Formation of an embryonic supermassive star in the first galaxy

英語

first stars

2014-11-21

Oxford University Press

Monthly notices of the Royal Astronomical Society

445(1)

L109-L113

We studied the gravitational collapse of a warm (similar to 8000 K) primordial-gas cloud as a candidate progenitor for a supermassive star (SMS; a parts per thousand(3) 10(5) M-aS (TM)) using a three-dimensional hydrodynamical simulation including all the relevant cooling processes of both H-2 and H, which can potentially induce cloud fragmentation. This is the first simulation of this kind to resolve protostar formation. We find that from a weakly turbulent initial condition, the cloud undergoes runaway collapse without a major episode of fragmentation. Although the H-2 fraction jumps by a large factor via the three-body reaction at similar to 10(-13) g cm(-3), its cooling remains inefficient due to the optical thickness, and the temperature remains a parts per thousand(3) 3000 K. When the central core of the cloud becomes opaque to continuum radiation at similar to 10(-8) g cm(-3), a hydrostatic protostar with a parts per thousand integral 0.2 M-aS (TM) is formed. The protostar grows to the mass a parts per thousand integral 1 M-aS (TM) and the radius a parts per thousand integral 2 au within similar to 1 yr via rapid accretion of dense filamentary flows. With high accretion rate, similar to 2 M-aS (TM) yr(-1), the protostar is expected to turn into an SMS within its lifetime, eventually collapsing to a seed for the supermassive black hole observed in the early Universe at z similar to 7.

学術雑誌論文

Version of Record

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2014 The Authors Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved.

0035-8711

1365-2966