We know there are rouge stars floating in intergalactic space, thought to be caused by galactic collision. What other other classes of celestial object could be found floating around in intergalactic space?
Within galaxies there are the following types of object:
- Brown Dwarfs
- White Dwarfs
- Black Holes
- Neutron Stars
- Interstellar rogue planets
- Planetary Systems
- Star Systems
- Star Clusters
- Debris Disks
Which of these can possibly exist in intergalactic space? Asteroids and comets are probably quite common, but is it known for entire planetary systems to exist in intergalactic space? Even star clusters?
Out of all the possible types, could I also have a link / designation to each object thats been observed, floating in intergalactic space.
For example, here's an intergalactic star HE_0437-5439