Mapping the star formation history of Mrk 86^*

I. Data and models

¹ Departamento de Astrofísica, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid, Spain
² OTRI, Universidad Carlos III de Madrid, C/ Butarque, 15, E-28911 Leganés, Spain e-mail: gil@astrax.fis.ucm.es (AGdP)

Received: 23 November 1999
Accepted: 8 June 2000

Abstract


We have obtained optical (BVR, [OIII]λ5007 Å and Hα), 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 Hα luminosity distributions of the galaxy star-forming regions show maxima at and . The underlying stellar population shows an exponential surface brigthness profile with central value, , and scale,  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, , and burst strength, 1-10^-4. These models include nebular continuum and recombination and forbidden-line emission.