The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. II. Results

Understand

The spectral absorption lines in early-type galaxies contain a wealth of information regarding the detailed abundance pattern, star formation history, and stellar initial mass function (IMF) of the underlying stellar population.

• Using our new population synthesis model that accounts for the effect of variable abundance ratios of 11 elements, we analyze very high quality absorption line spectra of 38 early-type galaxies and the nuclear bulge of M31.
• These data extend to 1um and they therefore include the IMF-sensitive spectral features NaI, CaII, and FeH at 0.82um, 0.86um and 0.99um, respectively.
• The models fit the data well, with typical rms residuals ~1%.