In astronomy, a RAMBO or robust association of massive baryonic objects is a dark cluster

Star cluster

Star clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain less than...

 made of brown dwarfs or white dwarfs.

Introduction

RAMBOs were proposed by Moore and Silk in 1995. They may have effective radii between 1 and 15 pc, with masses in the range 10–100,000 (solar masses).

Dynamics

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. Theoretically, these very long-lived objects could exist in large numbers. The presence of a clustered thick disk-like component of dark matter

Dark matter

In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...

 in the Galaxy

Milky Way

The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...

 has been suggested by Sanchez-Salcedo (1997, 1999) and Kerins (1997).

See also

• Dark matter
  Dark matter
  In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...
  
  
• Brown dwarfs
• White dwarfs
• Microlensing
• Hypercompact stellar system
  Hypercompact stellar system
  A hypercompact stellar system is a dense cluster of stars around a supermassive black hole that has been ejected from the centre of its host galaxy...
  
  
• Massive compact halo object
  Massive compact halo object
  Massive astrophysical compact halo object, or MACHO, is a general name for any kind of astronomical body that might explain the apparent presence of dark matter in galaxy halos. A MACHO is a body composed of normal baryonic matter, which emits little or no radiation and drifts through interstellar...
  
   (MACHOs)
• Weakly interacting massive particles (WIMPs)