Ultra-deep Imaging of the Starless Galaxy Candidate Cloud-9
We report the non-detection of stellar light associated with the dark galaxy candidate Cloud-9. Ultra-deep imaging obtained with HiPERCAM at the Gran Telescopio Canarias (GTC) reaches surface-brightness limits of 31.4 and 31.0 mag arcsec−2 in g and r, respectively, approximately ten times deeper than previous deep imag...