I am assuming you've seen this: http://thegradcafe.com/survey/index.php ... ard+astro*
When I was rejected from Harvard Astronomy in 2012, the only thing I got was a very nice letter in the mail stating the bad news. I received this letter in the middle of February though. In 2012 (and in other years, including this one), it seems like their acceptances were notified in early February.
So, based on the results search and my past experience, it is probably not going to be good news unfortunately
. It might be taking you awhile to get your letter in the mail though. Or it might be because you are not yet rejected as they wait to hear back from their top selections!