The PHANGS-MUSE survey -- Probing the chemo-dynamical evolution of disc
  galaxies
  We present the PHANGS-MUSE survey, a programme using the MUSE IFS at the ESO
VLT to map 19 massive $(9.4 < \log(M_{*}/M_\odot) < 11.0)$ nearby (D < 20 Mpc)
star-forming disc galaxies. The survey consists of 168 MUSE pointings (1'x1'
each), a total of nearly 15 Million spectra, covering ~1.5 Million independent
spectra. PHANGS-MUSE provides the first IFS view of star formation across
different local environments (including galaxy centres, bars, spiral arms) in
external galaxies at a median resolution of 50~pc, better than the mean
inter-cloud distance in the ionised interstellar medium. This `cloud-scale'
resolution allows detailed demographics and characterisations of HII regions
and other ionised nebulae. PHANGS-MUSE further delivers a unique view on the
associated gas and stellar kinematics, and provides constraints on the star
formation history. The PHANGS-MUSE survey is complemented by dedicated ALMA
CO(2-1) and multi-band HST observations, therefore allowing us to probe the key
stages of the star formation process from molecular clouds to HII regions and
star clusters. This paper describes the scientific motivation, sample
selection, observational strategy, data reduction and analysis process of the
PHANGS-MUSE survey. We present our bespoke automated data-reduction framework,
which is built on the reduction recipes provided by ESO, but additionally
allows for mosaicking and homogenisation of the point spread function. We
further present a detailed quality assessment and a brief illustration of the
potential scientific applications of the large set of PHANGS-MUSE data products
generated by our data analysis framework. The data cubes and analysis data
products described in this paper represent the basis for the first PHANGS-MUSE
public data release and are available in the ESO archive and via the Canadian
Astronomy Data Centre.
