brown dwarfs and quasars separated again

My loyal reader will recall that I spent the summer writing code to separate quasars and brown dwarfs using proper motions, measured in very low signal-to-noise data (that is, multi-epoch data in which the source is not detectable at any individual epoch), and that I spent the spring re-writing that code with the help of Lang. Today we finally closed the loop and showed that indeed we can separate the two populations using angular kinematics:


  1. Cool! Do you then separate green points from white points by colour?

  2. No, they are found by (very expensive) spectroscopic follow-up, by Fan and Jiang and others.

  3. My new hobby: using double entendres to get Hogg to respond to satirical comments on his blog