Properties of ETGs in compact groups of galaxies

We also selected a field sample composed of 846 ETGs to investigate environmental effects on galaxy evolution. We find that the dependences of mean stellar ages, [Z/H] and [{alpha}/Fe] on central stellar velocity dispersion are similar, regardless where the ETG resides, CGs or field.

When compared to the sample of centrals and satellites from the literature, we find that ETGs in CGs behave similarly to centrals, especially those embedded in low-mass haloes (M_h_<10^12.5^M_{sun}_). Except for the low-mass limit, where field galaxies present a star-forming signature, not seen in CGs, the ionization agent of the gas in CG and field galaxies seem to be similar due to hot, evolved low-mass stars. However, field ETGs present an excess of H{alpha} emission relative to ETGs in CGs.