Good Morning DA,

This is interesting. The investigators, McClintock and Narayan, that this article refers to used information gathered by RXTE. (That's the Rossi X-ray Timing Explorer satellite.) This project has come up with a number of interesting result. Some of them are listed here:

http://heasarc.nasa.gov/docs/xte/whatsnew/xte_notices_2006.html

One thing I find very interesting is the number of PhD's this satellite is generating!

Dr. R.