The Munich Near-Infrared Cluster Survey - I. Field selection, object extraction and photometry

The Munich Near-Infrared Cluster Survey (MUNICS) is a wide-area, medium-deep, photometric survey selected in the K' band. It covers an area of roughly 1deg² in the K' and J near-IR passbands. The survey area consists of 16 6×6arcmin² fields targeted at QSOs with redshifts 0.5<z<2 and seven 28×13arcmin² strips targeted at `random' high Galactic latitude fields. 10 of the QSO fields were additionally imaged in R and I, and 0.6deg² of the randomly selected fields were also imaged in the V, R and I bands. The resulting object catalogues were strictly selected in K', having a limiting magnitude (50 per cent completeness) of K'~19.5mag and J~21mag, sufficiently deep to detect passively evolving systems up to a redshift of z<~1.5 and luminosity of 0.5L*. The optical data reach a depth of roughly R~23.5mag. The main scientific aims of the project are the identification of galaxy clusters at redshifts around unity and the selection of a large sample of field early-type galaxies at 0<z<1.5 for evolutionary studies. In this paper - the first in a series - we describe the concept of the survey, the selection of the survey fields, the near-IR and optical imaging and data reduction, object extraction, and the construction of photometric catalogues. Finally, we show the J-K' versus K' colour-magnitude diagram and the R-J versus J-K', V-I versus J-K', and V-I versus V-R colour-colour diagrams for MUNICS objects, together with stellar population synthesis models for different star formation histories, and conclude that the data set presented is suitable for extracting a catalogue of massive field galaxies in the redshift range 0.5<~z<~1.5 for evolutionary studies and follow-up observations.