In astronomy, a RAMBO or robust association of massive baryonic objects is a dark cluster made of brown dwarfs or white dwarfs.
RAMBOs were proposed by Moore and Silk in 1995. They may have an effective radius between 1 and 15 parsecs, with masses in the range 10–100,000 M☉.[1]
The name is a contrived acronym referencing the character John Rambo, in the mold of similar acronyms in astrophysics such as "MACHO" and "WIMP".
The dynamics of these objects, if they do exist, must be quite different from that of standard star clusters. With a very narrow mass range (all brown dwarfs or white dwarfs), the evaporation rate of these RAMBOs should be very slow as predicted by the evolution of simulated mono-component cluster models.[2] Theoretically, these very long-lived objects could exist in large numbers. The presence of a clustered thick disk-like component of dark matter in the Galaxy has been suggested by Sanchez-Salcedo (1997, 1999) and Kerins (1997).[3][4][5]