PI: Renbin Yan, New York University, email@example.com
Address: Center for Cosmology and Particle Physics, 4 Washington Place, New York, NY 10003, USA
CoI: Michael Blanton, New York University
CoI: Luis Ho, Carnegie Observatories
Title: Probing the Warm Ionized Gas in Nearby Early-type Galaxies
Abstract: Most early-type galaxies contain warm ionized gas, detectable through optical emission lines. How is it ionized? Where does the gas come from? Are they from stellar mass loss or accreted from the outside? We will answer these questions by measuring multiple line ratio gradients in nearby early-type galaxies with long-slit spectroscopy. The line ratio gradients will probe the gas density profile and the ionizing flux profile, thus constraining the ionizing source distributions. It will also allow measurements of the gas-phase metallicity gradients. Demonstrating this capability in early-type galaxies will open a new window on the study of their evolution: comparing the gas metallicity with the stellar metallicity will reveal the origin of the gas. The DBSP on the Hale Telescope is the best instrument to cover all the necessary spectral features with sufficient spectral and spatial resolution. No other IFU or long-slit spectrographs available through NOAO can do this nearly as efficiently. Existing data either do not cover all the necessary spectral features or do not have sufficient quality or spatial resolution.
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