HI-observations of blue compact dwarf galaxies. II.^*

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: huchtmeier@mpifr-bonn.mpg.de
² Byurakan Astrophysical Observatory and Isaac Newton Institute of Chile, Armenian Branch, Byurakan 378433, Armenia e-mail: artptrs@yahoo.com
³ NCRA-TIFR, Pune University Campus, Pune 411 007, India e-mail: krishna@ncra.tifr.res.in
⁴ Institut d'Astrophysique, 75014 Paris, France e-mail: kunth@iap.fr

Received: 29 May 2006
Accepted: 14 October 2006

Abstract

We present new results from HI observations of previously undetected 69 blue compact dwarf galaxies (BCDGs) of which 35 BCDGs have been detected (detection rate 51%). Optical data (e.g., from NED) and other literature search are used to estimate the likelihood of confusion from other galaxies within the Effelsberg beam. We have combined 24 BCDG galaxies from this study and from Paper I (Huchtmeier et al. 2005) that are unlikely to suffer from confusion effects in combination with 19 other similar BCDGs taken from the literature to infer several characteristic properties of the BCDG population. 
The parameters which were used for the statistical analysis include linear diameter, axial ratio, blue luminosity, HI and total masses, HI and total mass-to-blue luminosity ratios, HI to total mass ratio, HI gas velocity dispersion, oxygen abundance, equivalent width of Hβ emission line and color. The analysis has revealed that: BCDGs with higher HI mass tend to have lower abundances of heavy elements and are more compact; BCDGs with lower blue luminosity have larger equivalent width of Hβ emission line and bluer colors, as well as a tendency towards lower abundances of heavy elements; BCDGs with larger linear size, with higher total mass and those with higher total and HI mass per unit blue luminosity, tend to have broader HI emission line (larger velocity dispersion); there is no obvious dependence of the star formation parameters on the total mass; almost 10% of the BCDGs emit milli-Jansky level radio continuum near 1 GHz.