Аннотация
We present the first ab initio cosmological simulations of a CR7-like object
which approximately reproduce the observed line widths and strengths. In our
model, CR7 is powered by a massive (2.23 x 10^7 M_Sun), accreting (0.25
Eddington) supermassive black hole (BH). Our model takes into account
multi-dimensional effects, X-ray feedback, secondary ionizations and primordial
chemistry. We estimate Ly-alpha line widths by post-processing simulation
output with Monte Carlo radiative transfer and calculate emissivity
contributions from radiative recombination and collisional excitation. We find
the luminosities in the Lyman-alpha and He II 1640 angstrom lines to be 5.0 x
10^44 and 2.4 x 10^43 erg/s, respectively, in agreement with the observed
values of > 8.3 x 10^43 and 2.0 x 10^43 erg/s. We also find that the black hole
heats the halo and renders it unable to produce stars as required to keep the
halo metal free. These results demonstrate the viability of the BH hypothesis
for CR7 in a cosmological context. Assuming the BH mass and accretion rate that
we find, we estimate the synchrotron luminosity of CR7 to be P ~ 10^40 - 10^41
erg/s, which is sufficiently luminous to be observed in muJy observations and
would discriminate this scenario from one where the luminosity is driven by
Population III stars.
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