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| Paper: |
Kinematic Signs of Halo Substructure in Spiral Galaxies |
| Volume: |
421, Galaxies in Isolation: Exploring Nature Versus Nurture |
| Page: |
259 |
| Authors: |
Herrmann, K. A.; Ciardullo, R.; Sigurdsson, S. |
| Abstract: |
We present the results from a kinematic study of planetary nebulae (PNe) in five face-on spiral galaxies: IC 342, M74, M83, M94, and M101. We find that in the inner regions of the galaxies, the vertical velocity dispersion (σz) generally falls off exponentially with the light, as expected for a constant mass-to-light ratio (M/L), constant scale height (hz) disk. However, beyond three optical scale lengths (hR), σz asymptotes out at roughly 20 km s-1. Our analysis finds evidence for significant flaring in the outer regions as well, especially in M94. Our observations are in excellent agreement with predictions derived from models of disk heating by halo substructure. |
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