How do I pass _SESSION('userName') from this Zend_Auth method to the layout?

I'm having a difficult time understanding how Zend_Session_Namespace is integrated with Zend_Auth. I have this method I'm using as the action to Authenticate my login page-it is working correctly and redirecting to the /monthly view:

 public function authAction(){
    $request    = $this->getRequest();
    $registry   = Zend_Registry::getInstance();
    $auth       = Zend_Auth::getInstance(); 

    $DB = $registry['DB'];

    $authAdapter = new Zend_Auth_Adapter_DbTable($DB);
    $authAdapter->setTableName('users')
                ->setIdentityColumn('UserName')
                ->setCredentialColumn('Password');    

// Set the input credential values
    $uname = $request->getParam('UserName');
    $paswd = $request->getParam('Password');
    $authAdapter->setIdentity($uname);
    $authAdapter->setCredential($paswd);

   // Perform the authentication query, saving the result
    $result = $auth->authenticate($authAdapter);

       // TRYING TO SET THE NAMESPACE
        $this->session = new Zend_Session_Namspace('UserName');

    if($result->isValid()){
        $data = $authAdapter->getResultRowObject(null,'password');
        $auth->getStorage()->write($data);
        $this->_redirect('/monthly');

    }else{
        $this->_redirect('/login');
    }
}

But I need to be able to store UserName as a Zend_session and call it from monthly controller. I'm not doing things right because I just get a blank screen when I try and do this:

public function indexAction()
{

$this->view->userName = Zend_Session_Namespace('UserName');
}

With the lines:

$data = $authAdapter->getResultRowObject(null,'password');
$auth->getStorage()->write($data);

You're writing all the user's information, except the password, which is OK. Where ever you need to access the logged in user's details, you can do something like (updated as per your comment):

public function indexAction() {
    $auth = Zend_Auth::getInstance();
    if($auth->hasIdentity()) {
        $userData = $auth->getIdentity();
        $this->view->user = $userData;
    }
}

in the view file (index.phtml) just: echo $this->user->firstname

That's it. If one day you decide to change the storage for Zend_Auth from session, to, for example, database, this piece of code will still work.