The nature of the Lyman Alpha Emitter CR7: a persisting puzzle
  The peculiar emission properties of the $z \sim 6.6$ Ly$\alpha$ emitter CR7
have been initially interpreted with the presence of either a direct collapse
black hole (DCBH) or a substantial mass of Pop III stars. Instead, updated
photometric observations by Bowler et al. (2016) seem to suggest that CR7 is a
more standard system. Here we confirm that the original DCBH hypothesis is
consistent also with the new data. Using radiation-hydrodynamic simulations, we
reproduce the new IR photometry with two models involving a Compton-thick DCBH
of mass $\approx 7 \times 10^6 \, \mathrm{M_{\odot}}$ accreting (a) metal-free
($Z=0$) gas with column density $N_H = 8 \times 10^{25} \, \mathrm{cm^{-2}}$,
or (b) low-metallicity gas ($Z = 5 \times 10^{-3} \, \mathrm{Z_{\odot}}$) with
$N_H = 3 \times 10^{24} \, \mathrm{cm^{-2}}$. The best fit model reproduces the
photometric data to within $1 \sigma$. Such metals can be produced by weak
star-forming activity occurring after the formation of the DCBH. The main
contribution to the Spitzer/IRAC $3.6 \, \mathrm{\mu m}$ photometric band in
both models is due to HeI/HeII $\lambda 4714, 4687$ emission lines, while the
contribution of [OIII] $\lambda 4959, 5007$ emission lines, if present, is
sub-dominant. Spectroscopic observations with JWST will be required to
ultimately clarify the nature of CR7.
