Root acces to databases without being prompted for password

Hello!

I've "inherited" a pgsql database (in linux server, already configured and set up) and i noticed that the root user can access a particular database without being prompted for password (using the psql command).

I assume it's something related to database ownership and user permissions but i can't find exactly what is causing this.

I'd like to replicate this behaviour for other database since my goal is to use the root user for executing cron task (where a password prompts is highly annoying)

Any help will be appreciated, thanks in advance!

Rafael