  We compare surface maps of the chemically peculiar star HD 50773 produced
with a Bayesian technique and based on high quality CoRoT photometry with those
derived from rotation phase resolved spectropolarimetry. The goal is to
investigate the correlation of surface brightness with surface chemical
abundance distribution and the stellar magnetic field.
  The rotational period of the star was determined from a nearly 60 day long
continuous light curve obtained during the initial run of CoRoT. Using a
Bayesian approach to star-spot modelling, which in this work is applied for the
first time for the photometric mapping of a CP star, we derived longitudes,
latitudes and radii of four different spot areas. Additional parameters like
stellar inclination and the spot's intensities were also determined. The CoRoT
observations triggered an extensive ground-based spectroscopic and
spectropolarimetric observing campaign and enabled us to obtain 19 different
high resolution spectra in Stokes parameters I and V with NARVAL, ESPaDOnS, and
SemelPol spectropolarimeters.
  Doppler and Magnetic Doppler imaging techniques allowed us to derive the
magnetic field geometry of the star and the surface abundance distributions of
Mg, Si, Ca, Ti, Cr, Fe, Ni, Y, and Cu. We find a dominant dipolar structure of
the surface magnetic field. The CoRoT light curve variations and abundances of
most elements mapped are correlated with the aforementioned geometry: Cr, Fe,
and Si are enhanced around the magnetic poles and coincide with the bright
regions on the surface of HD 50773 as predicted by our light curve synthesis
and confirmed by photometric imaging.
