The 2009 Rossi Prize has been awarded to three scientists for their work on the measurements of masses of black holes in the Milky Way. Precisely determining the masses of these compact objects, which are found in binary pairs with companion stars, established that they were too massive to be neutron stars and were instead black holes. The recipients, in alphabetical order, are Charles D. Bailyn (Yale University), Jeffrey E. McClintock (Harvard-Smithsonian Center for Astrophysics), and Ronald A. Remillard (Massachusetts Institute of Technology).
The AAS High Energy Astrophysics Division (HEAD) awards the Rossi Prize in recognition of significant contributions as well as recent and original work in high-energy astrophysics. The prize is in honor of Professor Bruno Rossi, an authority on cosmic ray physics and a pioneer in the field of X-ray astronomy. The prize also includes an engraved certificate and a $1,500 award. The winners of the Rossi Prize will give a joint lecture at the 215th AAS meeting in January 2010 in Washington, DC.