Star formation in collisional ring galaxies are concentrated in spoke-like structures which terminate in a ring that result from a drop-through collision between two galaxies. While the formation of collisional ring galaxies are well-understood, observations have revealed the star-forming ISM to be surprisingly deficient of molecular gas even though ring galaxies are observed to be HI-rich and strongly star-forming. Current studies hypothesise that the compression-driven star formation found in the star-forming ring is likely to suffer from the immediate feedback effects of star formation which enhances the photodissociation rate of the molecular clouds that are confined within the ring. Using the EAGLE suite of cosmological simulations, I find the global ISM of ring galaxies to have lower pressure and metallicities than normal star-forming disk galaxies. The collisional interaction is responsible for decreasing the ISM pressure internal to the ring as the ISM is swept up by the density wave towards the ring. On the other hand, at the radius of the ring, the star formation efficiency of ring galaxies is indistinguishable from that of normal star-forming disk galaxies, and thus the main reason for their integrated lower efficiency is the different gas surface density profiles.
Unless announced otherwise, the lunch talks start at 12:30 sharp. The approximate duration of the lunch talk is given above, and additional time will be given for questions and discussion following the presentation. Please make sure that you take ample time to pick up your lunch beforehand.
Information for Speakers and Hosts: Talks by internal speakers are limited to 20 minutes, with additional time for questions. Visiting speakers can have up to 30 minutes, with additional time for questions. Hosts are responsible for bringing the speaker to the correct room in ample time to set up laptops etc., and for ensuring the speaker also has time for lunch.
For questions and/or suggestions concerning the lunch talks, please contact Themiya Nanayakkara () or Alvaro Hacar ()).