Which relation between Type.GetProperty and a readonly property

I've got the following class:

public sealed class ImmutableObject {

         public readonly int ic;

         public ImmutableObject(int value) {
             ic = value;
         }
}

Then I created a method that tries to obtain reflection informations by this class:

public static void infosByImmutableObject() {
         ImmutableObject iobj = new ImmutableObject(1);

         Console.WriteLine(iobj.ic);

         Type typeIobj = iobj.GetType();

         PropertyInfo infos = typeIobj.GetProperty("ic");

}

I can't undestand why, altough ic is public, infos remains null, and if I try with Type.getProperties the resulting array has zero elements. I noticed that, whitout the readonly modifier, GetProperties("ic") returns. How a public field is seen by GetProperty() when the readonly is present?