Nearby early-type galaxies with ionized gas: VI. The Spitzer-IRS view. Basic data set analysis and empirical spectral classification 🟉, 🟉 🟉
Context. A large fraction of early-type galaxies (ETGs) shows emission lines in their optical spectra, mostly with LINER characteristics. Despite the number of studies, the nature of the ionization mechanisms is still debated. Many ETGs also show several signs of rejuvenation episodes. Aims. We aim...
Astronomy & Astrophysics