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 1 deg² in the K′ and J near-IR passbands. The survey area consists of 16 6×6 arcmin² fields targeted at QSOs with redshifts 0.5<z<2 and seven 28×13 arcmin² strips targeted at ‘random’ high Galactic latitude fields. 10 of the QSO fields were additionally imaged in R and I, and 0.6 deg² 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′∼19.5 mag and J∼21 mag, 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∼23.5 mag. 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.