Palomar/Las Campanas Imaging Atlas of blue compact dwarf galaxies. I. Images and integrated photometry

We present B, R, and Halpha images for a total of 114 nearby galaxies (v(helio) < 4000 km s(-1)) that, with exception of nine objects, are classified as blue compact dwarfs (BCDs). BR integrated magnitudes, H alpha fluxes and H alpha equivalent widths for all the objects in the sample are presented. A new set of quantitative, observational criteria for a galaxy to be classified as a BCD is proposed. These criteria include a limit on the K-band luminosity (i.e., stellar mass; M-K > -21 mag), peak surface brightness (mu(B;peak) < 22 mag arcsec(-2)), and color at the peak surface brightness (mu(B;peak) - mu(R;peak) less than or similar to 1). H alpha emission is detected in all but three sample galaxies. Typical color, absolute magnitude, and H alpha luminosity are (B - R) = 0.7 +/- 0.3 mag, M-B = -16.1 +/- 1.4 mag, and log (L-H alpha) = 40.0 +/- 0.6 (ergs s(-1)). Galaxies morphologically classified as nE and iE BCDs within our sample show lower H alpha equivalent widths and redder colors, on average, than the iI- and i0-type BCDs. For most of the galaxies the presence of an evolved stellar population is required to explain their observed properties; only the most metal-poor BCDs (e.g., I Zw 18, Tol 65) are still compatible with a pure, young burst. The flux-calibrated and WCS-compliant images in this Atlas are individually available through the NASA/IPAC Extragalactic Database (NED) image server and collectively through a dedicated Web page.