%0 Generic %1 boettcher2017detection %A Boettcher, Erin %A Gallagher III, J. S. %A Zweibel, Ellen G. %D 2017 %K diffuse extraplanar gas m83 %T Detection of Extraplanar Diffuse Ionized Gas in M83 %U http://arxiv.org/abs/1707.08126 %X We present the first kinematic study of extraplanar diffuse ionized gas (eDIG) in the nearby, face-on disk galaxy M83 using optical emission-line spectroscopy from the Robert Stobie Spectrograph on the Southern African Large Telescope. We use a Markov Chain Monte Carlo method to decompose the NII$łambdałambda$6548, 6583, H$\alpha$, and SII$łambdałambda$6717, 6731 emission lines into HII region and diffuse ionized gas emission. Extraplanar, diffuse gas is distinguished by its emission-line ratios (NII$łambda$6583/H$1.0$) and its rotational velocity lag with respect to the disk ($\Delta v = -24$ km/s in projection). With interesting implications for isotropy, the velocity dispersion of the diffuse gas, $\sigma = 96$ km/s, is a factor of a few higher in M83 than in the Milky Way and nearby, edge-on disk galaxies. The turbulent pressure gradient is sufficient to support the eDIG layer in dynamical equilibrium at an electron scale height of $h_z = 1$ kpc. However, this dynamical equilibrium model must be finely tuned to reproduce the rotational velocity lag. There is evidence of local bulk flows near star-forming regions in the disk, suggesting that the dynamical state of the gas may be intermediate between a dynamical equilibrium and a galactic fountain flow. As one of the first efforts to study eDIG kinematics in a face-on galaxy, this study demonstrates the feasibility of characterizing the radial distribution, bulk velocities, and vertical velocity dispersions in low-inclination systems.

@misc{boettcher2017detection, abstract = {We present the first kinematic study of extraplanar diffuse ionized gas (eDIG) in the nearby, face-on disk galaxy M83 using optical emission-line spectroscopy from the Robert Stobie Spectrograph on the Southern African Large Telescope. We use a Markov Chain Monte Carlo method to decompose the [NII]$\lambda\lambda$6548, 6583, H$\alpha$, and [SII]$\lambda\lambda$6717, 6731 emission lines into HII region and diffuse ionized gas emission. Extraplanar, diffuse gas is distinguished by its emission-line ratios ([NII]$\lambda$6583/H$\alpha \gtrsim 1.0$) and its rotational velocity lag with respect to the disk ($\Delta v = -24$ km/s in projection). With interesting implications for isotropy, the velocity dispersion of the diffuse gas, $\sigma = 96$ km/s, is a factor of a few higher in M83 than in the Milky Way and nearby, edge-on disk galaxies. The turbulent pressure gradient is sufficient to support the eDIG layer in dynamical equilibrium at an electron scale height of $h_{z} = 1$ kpc. However, this dynamical equilibrium model must be finely tuned to reproduce the rotational velocity lag. There is evidence of local bulk flows near star-forming regions in the disk, suggesting that the dynamical state of the gas may be intermediate between a dynamical equilibrium and a galactic fountain flow. As one of the first efforts to study eDIG kinematics in a face-on galaxy, this study demonstrates the feasibility of characterizing the radial distribution, bulk velocities, and vertical velocity dispersions in low-inclination systems.}, added-at = {2017-07-27T10:48:51.000+0200}, author = {Boettcher, Erin and Gallagher III, J. S. and Zweibel, Ellen G.}, biburl = {https://www.bibsonomy.org/bibtex/2b883f8021b7b82ed197218917f419d21/miki}, description = {[1707.08126] Detection of Extraplanar Diffuse Ionized Gas in M83}, interhash = {d4aa8e86a8f7ca72f22e48af080174c0}, intrahash = {b883f8021b7b82ed197218917f419d21}, keywords = {diffuse extraplanar gas m83}, note = {cite arxiv:1707.08126Comment: 19 pages, 11 figures, accepted for publication in the Astrophysical Journal}, timestamp = {2017-07-27T10:48:51.000+0200}, title = {Detection of Extraplanar Diffuse Ionized Gas in M83}, url = {http://arxiv.org/abs/1707.08126}, year = 2017 }