  Observational evidence suggests that some very large supermassive black holes
(SMBHs) already existed less than 1 Gyr after the Big Bang. Explaining the
formation and growth of the 'seeds' of these SMBHs is quite challenging. We
explore the formation of such seeds in the direct collapse scenario. Using 3D
hydrodynamical simulations, we investigate the impact of turbulence and
rotation on the fragmentation behavior of collapsing primordial gas in the
presence of a strong UV radiation background, which keeps the gas hot.
Additionally, we explore different ways in which the collapsing gas may be able
to stay hot, and thus limit fragmentation. Using a one-zone model, we examine
the interplay between magnetic fields, turbulence, and a UV radiation
background.
  Feedback processes from stars and black holes shape the interstellar medium
(ISM) out of which new generations of luminous objects form. To understand the
properties of these objects, e.g. the stellar initial mass function, it is
vital to have knowledge of the chemical and thermodynamical properties of the
feedback-regulated ISM. To better understand the chemo-thermal state and
fragmentation behavior of gas in high-redshift galaxies, we updated, improved,
and extended a photodissociation region code. Our computational code, PDR-Zz,
is described in detail. Using this code, a grid of models is run, covering a
sizable range in physical properties. This allows us to systematically explore
the overall impact of various feedback effects, both radiative and chemical, on
the chemical and thermal balance of the gas in different physical regimes.
