push notifications

I'm new to iOs development, and I have a question about how an app can receive a push notification while it's not running in background or in foreground.
I read that there's a kind of "invisible" background, where the app can receive a push notification starting from server, i think Skype or Facebook use this techinque when you receive a private message (infact you receive it also if the app is completely closed).
What I want to know is if in the same way we can start a request from an app that is closed asking to a server if there are new notifications every "x" minutes in an opposite way (it's not the server that sends, but is the client that asks)
My problem is that I don't want to mantain a notification server, whereas I prefer to let the app periodically run quieries to the server.
Is this possible? if yes, which are the iOs supported versions?

I just read up on the UILocalNotificaiton class and this line suggests that all you would do is irritate your users; " If the application is not frontmost and visible, the system displays the alert message, badges the application, and plays a sound—whatever is specified in the notification."

What you are trying to do is create a polling system from you app, but local notification is not designed to run a background process so you are out of luck.