I think there's something up with this ones spectrum. Firstly there is no data for the biggest spike and the Ha spike is way to the "right". Any ideas?
Maybe one of the controls again?
The big, unmarked spike is an 'airglow emission line', which is normally removed by the spectroscopic pipeline (there's a second, fainter, one next to it, almost on top of the Mg absorption line). Airglow lines are caused by atoms (or ions) and molecules in the upper atmosphere; the aurorae can be thought of as spectacularly bright airglow lines (I think the physical mechanism for 'exciting' and ionizing the ions is the same). The faint grey lines indicate the 'error bars'.
The H-alpha line is so far to the right (red) because the redshift is high (for a galaxy this bright): 0.23
Looks like an 'near the end of a starburst' galaxy spectrum to me.