New pieces of the ULX puzzle
Most ULXs are in
interacting/merging galaxies
(Swartz et al 2003)
2
Many ULXs are in
low-metallicity environments
(see Pakullšs work)
3
Tidal
interactions ā higher
star formation
Weaker
stellar wind ā higher
mass of the BH remnant
4
ULXs in star-forming
galaxies are young objects
Optical counterparts are O stars, OB
associations