The dependence of stellar age distributions on giant molecular cloud environment
Dobbs, Clare; Pringle, J.E.; Naylor, Tim
Date: 22 October 2013
Article
Journal
Monthly Notices of the Royal Astronomical Society: Letters
Publisher
Oxford University Press / Royal Astronomical Society
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Abstract
In this Letter, we analyse the distributions of stellar ages in giant molecular clouds (GMCs) in spiral arms, interarm spurs and at large galactic radii, where the spiral arms are relatively weak. We use the results of numerical simulations of galaxies, which follow the evolution of GMCs and include star particles where star formation ...
In this Letter, we analyse the distributions of stellar ages in giant molecular clouds (GMCs) in spiral arms, interarm spurs and at large galactic radii, where the spiral arms are relatively weak. We use the results of numerical simulations of galaxies, which follow the evolution of GMCs and include star particles where star formation events occur. We find that GMCs in spiral arms tend to have predominantly young (<10 Myr) stars. By contrast, clouds which are the remainders of spiral arm giant molecular asssociations that have been sheared into interarm GMCs contain fewer young (<10 Myr) stars and more ∼20 Myr stars. We also show that clouds which form in the absence of spiral arms, due to local gravitational and thermal instabilities, contain preferentially young stars. We propose that the age distributions of stars in GMCs will be a useful diagnostic to test different cloud evolution scenarios, the origin of spiral arms and the success of numerical models of galactic star formation. We discuss the implications of our results in the context of Galactic and extragalactic molecular clouds.
Physics and Astronomy
Faculty of Environment, Science and Economy
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