An Analysis of International Collaboration Network in Astronomy and Astrophysics through Co-authored Publications

This study is undertaken to explore international collaboration network in astronomy and astrophysics. It aims (1) to illustrate general characteristics of international collaboration network among astronomical institutions, (2) to demonstrate the dynamics of these properties of the network, and (3) to examine whether an institution’s research resources affect its centrality and relationships in the network. The study compiled 57,934 papers in six astronomical journals from 2001 to 2009. The sample consists of 606 astronomical institutions worldwide.
The results show that international collaboration is prevalent in modern astronomical community. Almost all countries and institutions have experienced international collaborations over the nine years. Yet there are significant individual differences in the extent of international collaboration among astronomical institutions. In the network, the Istituto Nazionale di Astrofisica (INAF) and European Southern Observatory (ESO) are the most notable actors with the highest values of centrality, while Japan Meteorological Agency (JMA) is the only institution that separated completely from others.
The international collaboration network gradually grew and expanded during the nine-year span analyzed; however, most institutions have undergone some but not radical changes in their positions and relationships in the network. Some organizations even maintain stable relationships with every foreign counterpart. Overall, there is no significant change in an institution’s preference for each of partners in the international collaboration network.
Moreover, the results show that astronomical institutions with advantaged resources are more likely to have more foreign partners and play an influential role in the international collaboration network. An institution with advantages of research manpower has faster growth rate of degree and betweenness centrality. Yet research resources do not positively affect an organization’s closeness centrality. The results show that an institution does not tend to shorten its access paths to others as it has more adequate research manpower. In terms of relationships, the influence of research resources on the co-authorship preference is not as significant as it is expected. It is indicated that astronomical institutions do not prefer counterparts with higher levels of research resources in international collaborations.
In general, “birds of a feather flock together” or “homophily” appears more often than “opposite attract” in the international collaboration network. Sturdy links are usually built by two peripheral institutions. Another indication is the significant effect of geographic closeness on the preference. Institutions apparently prefer foreign counterparts in neighbor countries to those in different regions.