Author rights are granted as soon as you create a work and fix it in some form.  This means that your rights start as soon as your pen hits paper, you save your work, or hit record.  Your rights fall into two categories:  Economic and Moral.

Economic rights give you the right to profit off of your work, authorize reproductions, and authorizing public performance.  Economic rights can be bought, sold or transferred by the author, usually via a contract. It is also known as copyright. 

Moral rights are the right to be identified as the author of the work, and the right to object to any distortion of the work that alters the way the world views the author.   Moral rights are perpetual and cannot be transferred except via testament when the author dies and even then, authors are still expected to be identified as the author of the work, although rights holders can object to any distortion of the work. 

For the purposes of this guide, we'll focus about the Economic side of Author Rights which is represented by copyright.

 When a work is co-authored, all authors are co-owners of copyright in the work and any member can sell their copyrights to another person or entity. 

When a work is made as part of contracted work, it is a work made for hire.  This means that unless another agreement exists, the hiring party owns the copyright of the work. This notably is different for academic faculty in practice, but case law does not exist to support this, Faculty are not creating research works under hire, unless otherwise specified. 

 Details on the ownership of work is defined in the U.S. Copyright Law, found in Title 17, Chapter 2 of the United States Code.