A population of faint low surface brightness galaxies in the Perseus
  cluster core
  We present the detection of 89 low surface brightness (LSB), and thus low
stellar density galaxy candidates in the Perseus cluster core, of the kind
named "ultra-diffuse galaxies", with mean effective V-band surface brightnesses
24.8-27.1 mag arcsec$^{-2}$, total V-band magnitudes -11.8 to -15.5 mag, and
half-light radii 0.7-4.1 kpc. The candidates have been identified in a deep
mosaic covering 0.3 square degrees, based on wide-field imaging data obtained
with the William Herschel Telescope. We find that the LSB galaxy population is
depleted in the cluster centre and only very few LSB candidates have half-light
radii larger than 3 kpc. This appears consistent with an estimate of their
tidal radius, which does not reach beyond the stellar extent even if we assume
a high dark matter content (M/L=100). In fact, three of our candidates seem to
be associated with tidal streams, which points to their current disruption.
Given that published data on faint LSB candidates in the Coma cluster - with
its comparable central density to Perseus - show the same dearth of large
objects in the core region, we conclude that these cannot survive the strong
tides in the centres of massive clusters.
