1 J.M. Shull, M.L. Giroux, S.V. Penton, J.. Tumlinson, J.T. Stocke, E.B. Jenkins, H.W. Moos, W.R. Oegerle, B.D. Savage, K.R. Sembach, D.G. York, J.C. Green, and B.E. Woodgate, The Astrophysical Journal 538, (2000).