Interpreting the Recent Upper Limit on the Gravitational Wave Background   from the Parkes Pulsar Timing Array
  We provide comments on the article by Shannon et al. (Sep 2015) entitled "Gravitational waves from binary supermassive black holes missing in pulsar observations". The purpose of this letter is to address several misconceptions of the public and other scientists regarding the conclusions of that work. 
The NANOGrav Collaboration
astro-ph.IM astro-ph.GA gr-qc