convert VBS to PowerShell

I have a vb script that will tell me who is logged into a certain application.  

dim oneSignAuth

set oneSignAuth = WScript.CreateObject("OneSignAuth.OneSignAuth")

Those 2 lines are getting the user logged into this application but I don't know how.  I don't know vbscript so what is the PowerShell equivalent of WScript.CreateObject ?     Or is there one?