TY - JOUR
T1 - The EDGE-CALIFA Survey
T2 - Evidence for Pervasive Extraplanar Diffuse Ionized Gas in Nearby Edge-on Galaxies
AU - Levy, Rebecca C.
AU - Bolatto, Alberto D.
AU - Sánchez, Sebastián F.
AU - Blitz, Leo
AU - Colombo, Dario
AU - Kalinova, Veselina
AU - López-Cobá, Carlos
AU - Ostriker, Eve C.
AU - Teuben, Peter
AU - Utomo, Dyas
AU - Vogel, Stuart N.
AU - Wong, Tony
N1 - Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved..
PY - 2019/9/10
Y1 - 2019/9/10
N2 - We investigate the prevalence, properties, and kinematics of extraplanar diffuse ionized gas (eDIG) in a sample of 25 edge-on galaxies selected from the CALIFA survey. We measure ionized gas scale heights from Hα and find that 90% have measurable scale heights with a median of kpc. From the Hα kinematics, we find that 60% of galaxies show a decrease in the rotation velocity as a function of height above the midplane. This lag is characteristic of eDIG, and we measure a median lag of 21 km s-1 kpc-1, which is comparable to lags measured in the literature. We also investigate variations in the lag with radius. H i lags have been reported to systematically decrease with galactocentric radius. We find both increasing and decreasing ionized gas lags with radius, as well as a large number of galaxies consistent with no radial lag variation, and investigate these results in the context of internal and external origins for the lagging ionized gas. We confirm that the [S ii]/Hα and [N ii]/Hα line ratios increase with height above the midplane as is characteristic of eDIG. The ionization of the eDIG is dominated by star-forming complexes (leaky H ii regions). We conclude that the lagging ionized gas is turbulent ejected gas likely resulting from star formation activity in the disk as opposed to gas in the stellar thick disk or bulge. This is further evidence for the eDIG being a product of stellar feedback and for the pervasiveness of this WIM-like phase in many local star-forming galaxies.
AB - We investigate the prevalence, properties, and kinematics of extraplanar diffuse ionized gas (eDIG) in a sample of 25 edge-on galaxies selected from the CALIFA survey. We measure ionized gas scale heights from Hα and find that 90% have measurable scale heights with a median of kpc. From the Hα kinematics, we find that 60% of galaxies show a decrease in the rotation velocity as a function of height above the midplane. This lag is characteristic of eDIG, and we measure a median lag of 21 km s-1 kpc-1, which is comparable to lags measured in the literature. We also investigate variations in the lag with radius. H i lags have been reported to systematically decrease with galactocentric radius. We find both increasing and decreasing ionized gas lags with radius, as well as a large number of galaxies consistent with no radial lag variation, and investigate these results in the context of internal and external origins for the lagging ionized gas. We confirm that the [S ii]/Hα and [N ii]/Hα line ratios increase with height above the midplane as is characteristic of eDIG. The ionization of the eDIG is dominated by star-forming complexes (leaky H ii regions). We conclude that the lagging ionized gas is turbulent ejected gas likely resulting from star formation activity in the disk as opposed to gas in the stellar thick disk or bulge. This is further evidence for the eDIG being a product of stellar feedback and for the pervasiveness of this WIM-like phase in many local star-forming galaxies.
KW - ISM: kinematics and dynamics
KW - galaxies: ISM
KW - galaxies: kinematics and dynamics
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U2 - 10.3847/1538-4357/ab2ed4
DO - 10.3847/1538-4357/ab2ed4
M3 - Article
AN - SCOPUS:85073065218
SN - 0004-637X
VL - 882
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 84
ER -