The first uses the new-to-C#-6 expression-bodied member syntax. It's equivalent to:
public object MyObject
{
get { return new object(); }
}
The second is also new to C# 6 - an automatically implemented read-only property. It's equivalent to:
private readonly object _myObject; // Except using an unspeakable name
public object MyObject
{
get { return _myObject; }
}
You can only assign to MyObject from within a constructor in the declaring class, which actually just assigns to the field instead.
(Both of these "equivalencies" are using old-school property declarations, where you always have get, set or both as blocks containing code.)
