Pinpointing the cosmic web between massive galaxy clusters I. The incidence of HI and OVI as WHIM tracers
Researchers used far-ultraviolet absorption spectroscopy from HST/COS to look for signatures of the warm-hot intergalactic medium (WHIM) in cosmic web filaments connecting massive galaxy clusters. They found that the incidence rates and covering fractions of WHIM tracers, specifically broad Ly-$ ext{ } ext{ } ext{ } ext{ }$ absorbers (BLAs) and OVI absorbers, are significantly higher than those of cold gas tracers like narrow Ly-$ ext{ } ext{ }$ absorbers (NLAs). This suggests warm-hot gas is prevalent in these inter-cluster filaments.