The Incidence, Geometry, and Kinematics of Extraplanar Gas in MaNGA Galaxies
Abstract
The efficiency of star formation in galaxies is regulated by the cycle of accretion and feedback processes in the circumgalactic medium. The geometry, kinematics, and multi-phase structure of circumgalactic gas are not well predicted by numerical simulations, so there is motivation to characterize these properties empirically by observing ionized gas around galaxies in both emission and absorption. Absorption-line studies are quite sensitive to diffuse gas at low column densities, but they are limited in scope because they require bright background sources, which are rare and offer pencil-beam probes of gas properties for individual galaxies. A complementary approach is to use optical emission lines to study extraplanar diffuse ionized gas, which can trace the spatial extent and kinematics of outflowing and inflowing gas. Using the unique dataset of spatially resolved spectroscopy from MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), we are developing techniques to identify galaxies with extraplanar gas on the basis of optical emission lines that extend above and below the plane of disk galaxies. Our initial results suggest that extraplanar gas is quite common among galaxies in the MaNGA sample, particularly among star-forming galaxies with inclination angles greater than 45 degrees, for which it is more straightforward to separate extraplanar gas from emission associated with the disk. These results on the incidence, geometry, and kinematics of extraplanar gas as a function of global galaxy properties provide important constraints on models of accretion and feedback in the circumgalactic medium.
- Publication:
-
American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016
- Bibcode:
- 2016AAS...22731207D