Publication Date:
2017-01-08
Description:
We report an early science discovery of the 12 CO(1–0) emission line in the collisional ring galaxy VII Zw466, using the Redshift Search Receiver instrument on the Large Millimeter Telescope Alfonso Serrano. The apparent molecular-to-atomic gas ratio either places the interstellar medium (ISM) of VII Zw466 in the H i -dominated regime or implies a large quantity of CO-dark molecular gas, given its high star formation rate. The molecular gas densities and star formation rate densities of VII Zw466 are consistent with the standard Kennicutt–Schmidt star formation law even though we find this galaxy to be H 2 -deficient. The choice of CO-to- H 2 conversion factors cannot explain the apparent H 2 deficiency in its entirety. Hence, we find that the collisional ring galaxy, VII Zw466, is either largely deficient in both H 2 and H i or contains a large mass of CO-dark gas. A low molecular gas fraction could be due to the enhancement of feedback processes from previous episodes of star formation as a result of the star-forming ISM being confined to the ring. We conclude that collisional ring galaxy formation is an extreme form of galaxy interaction that triggers a strong galactic-wide burst of star formation that may provide immediate negative feedback towards subsequent episodes of star formation – resulting in a short-lived star formation history or, at least, the appearance of a molecular gas deficit.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
