Extraplanar diffuse ionized gas in a small sample of nearby edge-on galaxies

We present narrowband Ha imaging data of a small survey of nearby edge-on s piral galaxies, aiming at the detection of 'extraplanar' diffuse ionized ga s (DIG). A few of our studied edge-on spirals show signs of disk-halo inter action (DHI), where extended line emission far above the galactic plane of these galaxies is detected. In some cases an extraplanar diffuse ionized ga s (eDIG) layer is discovered, e.g., NGC4634, NGC3044. while other galaxies show only filamentary features reaching into the halo (e.g., IC 2531) and s ome galaxies show no sign of eDIG at all. The extraplanar distances of the DIG layer in our narrowband Hoc images reach values of z less than or equal to 2 kpc above the galactic plane. The derived star formation rates (SFRs) from the Ha flux of the studied galaxies range from 0.05 - 0.7 M. yr(-1), neglecting a correction for internal absorption. The variation of the SFR v alues among our sample galaxies reflects the diversity of star formation wi thin this sample. A diagnostic diagram is introduced, which allows to predi ct the existence of gas halos in 'quiescent' galaxies based on the ratio S- 60/S-100 versus L-FIR/D-25(2) in this diagram. We compare the positions of the non-starburst galaxies with starburst galaxies, since these galaxies po pulate distinct positions in these diagrams.