University of Hull logo

Galaxy chemical evolution models: The role of molecular gas formation

Mollá, Mercedes; Díaz, Ángeles I.; Ascasibar, Yago; Gibson, Brad K.


Yago Ascasibar

Mercedes Mollá

Ángeles I. Díaz

Angeles I. Díaz


In our classical grid of multiphase chemical evolution models, star formation in the disc occurs in two steps: first, molecular gas forms, and then stars are created by cloud-cloud collisions or interactions of massive stars with the surrounding molecular clouds. The formation of both molecular clouds and stars are treated through the use of free parameters we refer to as efficiencies. In this work, we modify the formation of molecular clouds based on several new prescriptions existing in the literature, and we compare the results obtained for a chemical evolution model of theMilkyWay Galaxy regarding the evolution of the Solar region, the radial structure of the Galactic disc and the ratio between the diffuse and molecular components, H I /H 2 . Our results show that the six prescriptions we have tested reproduce fairly consistent most of the observed trends, differing mostly in their predictions for the (poorly constrained) outskirts of the Milky Way and the evolution in time of its radial structure. Among them, the model proposed by Ascasibar et al. (in preparation), where the conversion of diffuse gas into molecular clouds depends on the local stellar and gas densities as well as on the gas metallicity, seems to provide the best overall match to the observed data.

Journal Article Type Article
Publication Date Jun 11, 2017
Journal Monthly notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 468
Issue 1
Pages 305-318
Keywords Galaxy : abundances, Galaxy -- molecular gas, Galaxy -- star formation
Publisher URL
Copyright Statement © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Additional Information Copy of article first published in: Monthly notices of the Royal Astronomical Society, 2017, v.468.


You might also like

Downloadable Citations