Narrow-band {H}β images of star-formation regions in HII galaxies

Aims:Create a catalog of images of HII galaxies and their individual star-formation regions in order to study the distribution of the gas emission and their underlying stellar continuum.
Methods: We have used Hβ narrow-band images of 43 selected HII galaxies obtained at ESO NTT 3.58 m telescope using the SUSI2 camera.
Results: Surface photometric Hβ fluxes and equivalent widths for all objects and star-formation regions are presented in this catalog. A myriad of filamentary structure were found in the pure Hβ emission-line or continuum-subtracted images, probably attributed to expanding shells as a consequence of the star-formation activity. Our results indicate that the number of regions with high Hβ equivalent width or young regions increase with the instrumental resolution, showing that the instrumental resolution is a bias to determine the cluster ages. Therefore, we showed that some of the observed giant HII regions may have been formed by ensembles of unresolved star forming regions or candidates to host Super Star Clusters. Pure Hβ emission-line images, continuum contours and EW(Hβ) maps showing the morphology of the gaseous and stellar emission in HII galaxies and their individual star-formation regions were obtained. All calibrated continuum and Hβ emission line fluxes and the derived Hβ equivalent width images are available in fits format from http://www.on.br/astro/etelles/HIIgalaxies/Hbeta/.

Based on observations made with ESO NTT 3.5 m Telescope at the La Silla Observatory under programmen ID < 68.B-0678(A) > and < 70.B-0184(A) >. Tables [see full textsee full textsee full textsee full text], [see full textsee full textsee full textsee full text] and Figs. [see full textsee full textsee full textsee full text], [see full textsee full textsee full textsee full text] are only available in electronic form at http://www.aanda.org