Intergalactic HiiRegions Discovered in SINGG

A number of very small isolated HII regions have been discovered at projecteddistances up to 30 kpc from their nearest galaxy. These HII regions appear astiny emission line objects in narrow band images obtained by the NOAO Surveyfor Ionization in Neutral Gas Galaxies (SINGG). We present spectroscopicconfirmation of four isolated HII regions in two systems, both systems havetidal HI features. The results are consistent with stars forming in interactivedebris due to cloud-cloud collisions. The H-alpha luminosities of the isolatedHII regions are equivalent to the ionizing flux of only a few O stars each.They are most likely ionized by stars formed in situ, and represent atypicalstar formation in the low density environment of the outer parts of galaxies. Asmall but finite intergalactic star formation rate will enrich and ionize thesurrounding medium. In one system, NGC 1533, we calculate a star formation rateof 1.5e-3 msun/yr, resulting in a metal enrichment of ~1e-3 solar for thecontinuous formation of stars. Such systems may have been more common in thepast and a similar enrichment level is measured for the `metallicity floor' indamped Lyman-alpha absorption systems.