The mysterious habitats of type IIn supernovae

A new Hα survey of the environments of type IIn supernovae Type IIn supernovae (SNeIIn) are proposed to be a class of core-collapse supernovae (CCSNe) which occur within a dense circumstellar medium (CSM) that leads to the signature narrow component on H lines. SNeIIn are a fairly uncommon and mysterious SN type accounting for around 7% of all classified SNe. The mysteriousness of SNeIIn regards the progenitor path. CCSNe are the terminal explosions of high mass stars and the progenitors of SNeIIn are often attributed to Luminous Blue Variables (LBVs). Therefore, one would expect SNeIIn to be associated with regions of star formation. But Habergham et al. (2014) have suggested this may not be not the case. Those authors found that SNeIIn poorly trace Hα emission with a potential bimodal population in the association of star formation as traced by Hα with some sites being strongly associated and other being far away from areas of star formation. We present the findings from the largest Hα survey of the environments of SNeIIn yet undertaken. We investigate the possibility of bimodal levels of association with star formation which may suggest multiple progenitor paths. Potential lower mass progenitors being electron-capture supernovae or mergers which produce an LBV. Further to this some SNeIIn (notably SN2005ip) have long-lasting Hα emission long after the eruption. We will investigate whether any objects in our sample/the proportion of our sample exhibit this behaviour and also systematically spectrally re-classify the SNeIIn in our sample where data can be found.