TY - GEN
T1 - Origin and ionization of the warm ionized gas in massive early-type galaxies
AU - Yan, Renbin
AU - Blanton, Michael R.
PY - 2012/8
Y1 - 2012/8
N2 - Most early-type galaxies are not devoid of cold and warm gas. The origin and ionization of this gas reveal the intriguing ongoing evolution of these galaxies. In most cases, the warm ionized gas shows emission-line spectra similar to low-ionization nuclear emission-line regions (LINERs). Their ionization mechanism has been hotly debated. We will present evidence from line ratio gradient that rules out AGN and shocks as the dominant ionization mechanism, and suggests the ionizing sources follow the stellar density profile. Hot evolved stars are the favorite candidates but bring new puzzles. This finding allows us to obtain a gas-phase metallicity calibration in these early-type galaxies, using the line emission. We will show how the metallicity of the warm gas depends on stellar mass and stellar age, and what it tells us about the origin of the warm gas in these galaxies.
AB - Most early-type galaxies are not devoid of cold and warm gas. The origin and ionization of this gas reveal the intriguing ongoing evolution of these galaxies. In most cases, the warm ionized gas shows emission-line spectra similar to low-ionization nuclear emission-line regions (LINERs). Their ionization mechanism has been hotly debated. We will present evidence from line ratio gradient that rules out AGN and shocks as the dominant ionization mechanism, and suggests the ionizing sources follow the stellar density profile. Hot evolved stars are the favorite candidates but bring new puzzles. This finding allows us to obtain a gas-phase metallicity calibration in these early-type galaxies, using the line emission. We will show how the metallicity of the warm gas depends on stellar mass and stellar age, and what it tells us about the origin of the warm gas in these galaxies.
KW - cD
KW - galaxies: elliptical and lenticular
KW - galaxies:ISM
KW - stars: AGB and post-AGB
UR - http://www.scopus.com/inward/record.url?scp=84880440316&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84880440316&partnerID=8YFLogxK
U2 - 10.1017/S1743921313005279
DO - 10.1017/S1743921313005279
M3 - Conference contribution
AN - SCOPUS:84880440316
SN - 9781107033849
T3 - Proceedings of the International Astronomical Union
SP - 328
EP - 331
BT - The Intriguing Life of Massive Galaxies
A2 - Thomas, Daniel
A2 - Pasquali, Anna
A2 - Ferreras, Ignacio
ER -