A very milky way

• by wassock moderator

  Hi just trying to get all this data sorted in my head, so this is red shift 0.01 so fairly close to home and a smallish alpha H so cooling down ( or starting up?) on star formation?
  What's the great big OIII peak telling us?

  Posted July 22, 2013 5:03 PM

• by jules moderator

  As far as I'm aware it's a sure sign of star forming regions indicating lots of hot oxygen - like the Galaxy Zoo peas.

  Posted July 22, 2013 7:13 PM

• by JeanTate in response to wassock's comment.

  Fairly close to home, yes. The color is blue, and the continuum in the spectrum rises almost to 400nm, so there are, relatively speaking, a lot of hot stars. The nebular lines - [OIII], [NII], [SII] - are fairly weak (except for the main [OIII] 500.7nm one). It's a pretty ratty spectrum, but the Na, Mg, and Ca absorption lines are all pretty weak; perhaps in part because this galaxy has a low 'metallicity' (the proportion of elements heavier than He is waay smaller than that found in the Sun)?

  So? Likely a nearby dwarf galaxy, which recently had a burst of star-formation, but as it's a low metallicity galaxy, with little dust and a relatively low gas density, the star-formation is (or was) rather quiet, and spread throughout the galaxy? Quite a contrast to Green Peas!

  Posted July 23, 2013 3:51 PM

• by jules moderator

  And just as I disappear to read up more a brilliant answer appears! Thanks Jean. 😃

  Posted July 23, 2013 10:51 PM