Little Dots the ULX analogy

I consider recent observations of the Little Dots (LDs) observed in high-redshift (z ∼ 7) galaxies. I have suggested that the central black holes in these objects are probably fed mass at very super-Eddington (factors (Formula presented) ) rates. In physical terms, this idea makes them supermassive analogues of the (stellar-mass) ultraluminous X-ray sources (ULXs), whose hard X-ray emission is strongly anisotropic (‘beamed’). In this letter, I argue that the recent discovery of extended rest-frame hard X-ray ionization cones from an LD gives strong quantitative support to this view, as its geometry is what one would expect from a ULX-like object viewed not along one of its X-ray beams, but instead ‘from the side’, very similar to the extreme Galactic system SS433. This in turn agrees in quantitative terms with recent suggestions that LDs resemble supermassive versions of SS433-like systems. I emphasize that in contrast, the rest-frame soft X-ray emission from LDs must be roughly isotropic, and presumably power the torus emission observed from these galaxies.