Volume 396, Number 2, December III 2002
|Page(s)||503 - 512|
|Section||Cosmology (including clusters of galaxies)|
|Published online||03 December 2002|
Spectroscopic study of blue compact galaxies *
II. Spectral analysis and correlations
Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
2 Center for Astrophysics, University of Science and Technology of China, 230026, Hefei, PR China
3 Institut d'Astrophysique de Paris, CNRS, 98 bis boulevard Arago, 75014 Paris, France
Corresponding author: X. Kong, firstname.lastname@example.org; email@example.com
Accepted: 1 October 2002
This is the second paper in a series studying the star formation rates, stellar components, metallicities, and star formation histories and evolution of a sample of blue compact galaxies. We analyzed spectral properties of 97 blue compact galaxies, obtained with the Beijing Astronomical Observatory (China) 2.16 m telescope, with spectral range 3580 Å–7400 Å. We classify the spectra according to their emission lines: 13 of the total 97 BCG sample are non-emission line galaxies (non-ELGs); 10 have AGN-like emission (AGNs), and 74 of them are star-forming galaxies (SFGs). Emission line fluxes and equivalent widths, continuum fluxes, the 4000 Å Balmer break index and equivalent widths of absorption lines are measured from the spectra. We investigate the emission line trends in the integrated spectra of the star-forming galaxies in our sample, and find that: 1) The equivalent widths of emission lines are correlated with the galaxy absolute blue magnitude MB; lower luminosity systems tend to have larger equivalent widths. 2) The equivalent width ratio 6583/ is anti-correlated with equivalent width ; a relationship is given that can be used to remove the contribution from blended +6548, 6583. 3) The , , and fluxes are correlated; those can be used as star formation tracers in the blue. 4) The metallicity indices show trends with galaxy absolute magnitude and attenuation by dust, faint, low-mass BCGs have lower metallicity and color excess.
Key words: galaxies: active / galaxies: Seyfert / galaxies: general / galaxies: stellar content
© ESO, 2002
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