The relation between Ly<i>α</i>absorbers and local galaxy filaments

Context. The intergalactic medium (IGM) is believed to contain the majority of baryons in universe and trace same dark matter structure as galaxies, forming filaments sheets. Ly α absorbers, which sample neutral component IGM, have been extensively studied at low high redshift, but exact relation between absorption, large-scale observationally not well constrained. Aims. In this study, we aim characterising absorbers nearby over-dense cosmological structures (galaxy filaments) recession velocities Δ v ≤ 6700 km s −1 by using archival observational data from various instruments. Methods. We analyse 587 intervening spectra 302 extragalactic background sources obtained with Cosmic Origins Spectrograph (COS) installed on Hubble Space Telescope (HST). combine absorption line information galaxy five local V8k catalogue. Results. Along 91 sightlines that pass close a filament, identify 215 (227) systems (components). Among these, 74 are aligned position velocity filaments, indicating these galaxies structure. filament-aligned ∼90% higher rate incidence (d