Please Explain this

• by bernoullilemniscate

  The spectra diagram on SkyServer gives this object a class of QSO Starburst Broadline. I can understand the #Broadline as the H-alpha and H-beta lines or obviously broader than normal. The [OIII] at approximately 5250 angstroms is very strong. The strong [OIII] in my examinations seems to be associated blue star forming regions yet I see no evidence of star forming regions in the Sky Server image. I understand the QSO is an abbreviation for quasar, so what is there about this object that identifies this as a quasar?

  Posted June 8, 2015 7:03 PM

• by Capella05 moderator in response to bernoullilemniscate's comment.

  Have a look at the scale on the left axis - these emissions are not particularly strong. That would explain why the spectra results may seem a bit odd.

  Posted June 8, 2015 7:14 PM

• by mlpeck

  [O III] can be associated with an AGN, starforming region, or with planetary nebula emission (that's what makes high surface brightness planetary nebulae look greenish in a largish telescope). In any given spectrum you could be seeing either or both of an AGN and starforming regions.

  An SDSS spectro pipeline class of "QSO" basically just means the spectrum has a broadline emission component. A more traditional classification would call this a type I AGN or Seyfert, which is what all the literature that NED associates this object calls it.

  Posted June 8, 2015 8:34 PM

• by bernoullilemniscate

  Thanks for the help. The astronomy I took and read up on tends to date from the Early 1970s so I've got a lot of catching up to do. I imagine I learned Astronomy before a lot you were born.

  Posted June 9, 2015 6:32 PM

• by bernoullilemniscate in response to mlpeck's comment.

  I first learned about [OIII] lines studying planetary nebulae

  Posted June 9, 2015 6:34 PM

• by bernoullilemniscate in response to mlpeck's comment.

  Another question, l understand that [OIII] lines originate in conditions of very low density and very high excitation. Can you tell if the lines are from the remnants of the nebulae the the stars originate from or if they come from interstellar medium around the stars? I realize that there may not be much difference. or if OB stars can have have extended envelopes that produce these lines. Please bear with me as I have said my background is rather dated.

  Posted June 9, 2015 6:45 PM

• by Budgieye moderator

  I think OIII emission originates mostly in nebula. As the oxygen cloud recedes from its exploded star, the oxygen would stop being ionized.

  I found one article about oxygen around a star http://herschel.cf.ac.uk/mission/first_spectra , but I think oxygen tends to bond with carbon to form carbon monoxide as conditions cool.

  Black holes will heat oxygen http://phys.org/news/2009-05-intriguing-galaxy.html

  I would think colliding galaxies too.

  Posted June 12, 2015 3:12 AM