MUSE crowded field 3D spectroscopy in NGC300 I. First results from
  central fields
  Aims. As a new approach to the study of resolved stellar populations in
nearby galaxies, our goal is to demonstrate in NGC300 that integral field
spectroscopy with high spatial resolution and excellent seeing conditions
reaches an unprecedented depth in severely crowded fields.
  Methods. MUSE observations with seven pointings in NGC300 have resulted in
datacubes that are analyzed in four ways: (1) PSF-fitting 3D spectroscopy with
PampelMUSE yields deblended spectra of individually distinguishable stars. The
technique also provides samples of planetary nebulae that are complete down to
m5007=28. (2) pseudo-monochromatic images, created at the wavelengths of the
most important emission lines and corrected for continuum light by using the
P3D visualization tool, provide maps of HII regions, SNR, and the diffuse ISM
at a high level of sensitivity, allowing for the discovery of planetary
nebulae, WR stars etc. (3) The use of the P3D line-fitting tool yields emission
line fluxes, surface brightness, and kinematic information for gaseous objects,
corrected for absorption line profiles of the underlying stellar population.
(4) Visual inspection of the datacubes is demonstrated to be effcient for data
mining and the discovery of background galaxies and unusual objects.
  Results. We present a catalogue of luminous stars, rare stars such as WR and
other emission line stars, carbon stars, symbiotic star candidates, planetary
nebulae, HII regions, supernova remnants, giant shells, peculiar diffuse and
filamentary emission line objects, and background galaxies, along with their
spectra.
  Conclusions. The technique of crowded-field 3D spectroscopy is capable of
deblending individual bright stars, the unresolved background of faint stars,
gaseous nebulae, and the diffuse component of the interstellar medium,
resulting in unprecedented legacy value for observations of nearby galaxies
with MUSE.
