Assigned ID: 639 ----- Submission 1 (Sat Jan 22 00:43:25 GMT 2005) ----- The local "missing baryons" are predicted to be in a warm-hot low density phase, largely in the giant cosmic filaments that connect the denser virialized clusters and groups of galaxies. We have recently detected a high fraction of absorption systems towards the direction that connects galaxy clusters within superclusters, indicating the presence of the predicted cosmic filaments. The association between the absoption systems and individual clusters of galaxies is, however, a source of uncertainty in determining the nature of the detections. Here, we aim at improving the reliability of previous determination of absoption systems in the line of sight towards cosmic filaments by establishing a relation between absorption systems and galaxy cluster "halos". We will look for Ly\alpha absorption lines in the spectra of a large sample of background AGNs distributed at various projected distances from clusters of galaxies. This will be used to quantify the likelihood of competing scenarios to explain the recently detected series of absorption systems in cosmic filaments.

AGN/QUASARS 12 54819.00 standard - See attached pdf file. false 0.0 false false false false false SUPPORTED