New insights to the photometric structure of Blue Compact Dwarf Galaxies from deep Near-Infrared studies I. Observations, surface photometry and decomposition of surface brightness profiles

摘要

(shortened) We analyze deep Near Infrared (NIR) broad band images for asample of Blue Compact Dwarf Galaxies (BCDs), allowing for the quantitativestudy of their extended stellar low-surface brightness (LSB) host galaxies. NIRsurface brightness profiles (SBPs) of the LSB hosts agree at largegalactocentric radii with those from optical studies. At small to intermediateradii, however, the NIR data reveal for more than half of our sample asignificant flattening of the exponential SBP of the LSB host. Such SBPs ("typeV" SBPs, Binggeli & Cameron 1991) have rarely been detected in LSB hosts ofBCDs at optical wavelengths, where the relative flux contribution of thestarburst is stronger than in the NIR and can hide such central intensitydepressions of the LSB host. The structural properties, frequency and physicalorigin of type V LSB SBPs in BCDs and other dwarf galaxies have not yet beensystematically studied. Nevertheless, their occurrence in a significantfraction of BCDs would impose important new constraints to the radialdistribution of their stellar mass, and to the photometric fading of BCDs afterthe termination of star-forming activity. Both a modified exponential(Papaderos et al. 1996a) and the Sersic law give satisfactory empiricaldescriptions for type V SBPs. However, we argue that the practicalapplicability of Sersic fits to LSB SBPs of BCDs is limited by, e.g., theextreme sensitivity of the solutions to small SBP uncertainties. Most stellarLSB host galaxies in the sample show optical-NIR colors indicative of evolvedstellar populations with subsolar metallicity. Unsharp-masked NIR images andoptical-NIR maps reveal numerous morphological details, and cases ofnon-uniform dust absorption on spatial scales up to ~1 kpc.