Mapping the star formation history of Mrk 86 -: I.: Data and models

We have obtained optical (BVR, [O III]lambda 5007 Angstrom and H alpha), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk 86 (NGC 2537). In this paper, the first of two, we present optical-near-infrared colors and emission-line fluxes for the currently star-forming regions, intermediate aged starburst and underlying stellar population. We also describe the evolutionary synthesis models used in Paper II. The R and H alpha luminosity distributions of the galaxy star-forming regions show maxima at M-R = -9.5(m) and L-H alpha = 10(37.3) ergs(-l). The underlying stellar population shows an exponential surface brigthness profile with central value, mu(E),(0) = 21.5 mag arcsec(-2), and scale, alpha = 0.88 kpc, both measured in the R-band image. In the galaxy outer regions, dominated by this component, no significant color gradients are observed. Finally, a complete set of evolutionary synthesis models have been developed, covering a wide range in metallicity, 1/50 Z. < Z < 2 Z., and burst strength, 1-10(-4). These models include nebular continuum and recombination and forbidden-line emission.