I want to apply as a PhD candidate and therefore looking up on various potential supervisors who have common research interests. My approach is by first visiting their webpages, looking up on the Research Interests mentioned and then checking their recent publications on a particular topic I am interested in. I find many, but in most of them the potential supervisor is a second or a co-author.
In order to gauge the current active research field and work of the supervisor, must they be the first author or does being a co-author imply the same?
If this matters, my subject is Engineering and Technology.