Letters of Intent received in 2019

LoI 2021-2100
GA Symposium: Diversity in Conditions for and Products of Cosmic Star Formation

Topics

(1) To what extent do the observed properties of interstellar gas that control the star formation process (e.g., gas temperature and density) vary within, and differ between, galaxies? How do conditions for star formation evolve over cosmic time?

(2) To what extent do the observed properties of stellar populations produced by star formation (e.g., initial mass function and clustering) vary within, and differ between, galaxies? How does the outcome of the star formation process evolve over cosmic time?

(3) Based on theory, how should the outcome of the star formation process depend on the gas properties in galaxies and molecular clouds?

(4) Do observations establish clear correlations between gas properties and the characteristics of the newly–formed stars? Are these observed correlations consistent with theoretical predictions?

Rationale

Star formation is the key process that converts cosmic baryons into the stars that form the backbone of galaxy structure. A detailed understanding of the star formation process is therefore essential, if we wish to establish a coherent picture of how galaxies emerged over cosmic time.

It is clear that the properties of the stellar populations emerging from the star formation process — i.e., the total mass of newly–formed stars, the clustering of stellar groups, and the stellar initial mass function — should depend on the characteristics of the gas in the environments in which stars are born. On small spatial scales the birth conditions are set by the properties of molecular clouds, while galaxy–scale characteristics increasingly matter on larger spatial scales. Establishing connections between the properties of the gas and those of the newly–formed stars is essential for our grasp of the cosmic star formation process, since the properties of the gas evolved substantially over cosmic time.

Interestingly, observations on spatial scales ~1 kpc or more suggest a rather universal and simple connection between the star formation rate and mass of the reservoir of gas at relatively high density. These simple connections are, for example, expressed by the Kennicutt–Schmidt relation and the Gao & Solomon correlation. However, cloud–scale observations in the Milky Way suggest a more complex picture that is not captured by a single simple relation. Further, studies of nearby galaxies reveal that the properties of stellar clusters systematically vary within galaxies. This demonstrates that simple scaling laws might at best hold on very large spatial scales.

This meeting seeks to foster discussions between researchers from the fields of Galactic and extragalactic star formation, but also to enable dialogue between experts focusing on the diffuse interstellar medium, molecular clouds, and young stellar groups. At the very minimum, this meeting seeks to document our current knowledge about the diversity in the properties of young stellar groups and of star–forming gas throughout the cosmos. Ideally, this conference will identify ways in which the diversity in the properties of young stellar populations can be explained on the basis of the diversity in cosmic gas properties.