Models predict lots of gas and star formation in the central ring!
What do we see? (courtesy Higdon etal)
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Uh oh....
But wait...
| there is molecular gas
(Horellou etal 1998) MH2 ~ 1.5-6x109 Msun |
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| and there is mid-IR emission
indicative of star formation (Charmandaris etal 1999) ...just not as dominant as in the outer ring.
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