I believe there may be a case where this could be acceptable. It seems like you are thinking more of a filter specific to the authors content area, rather than a second search. You would need to work to distinguish the two components to ensure user expectations were clear, Filter vs. Search.
Assuming visitors to the authors page were looking for an individual author, an internal filter could work well. As the user types the content, the list of authors are filtered. Similar to the functionality in this example - http://codepen.io/JFarrow/pen/DwKap
If your site-wide search returns results as the user types (like Amazon) then maybe you are better working on categorising the real time results so user's can quickly & easily find authors from there.