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Detection of Intergalactic HeII Absorption at Redshift 3.5

W. Zheng·K. Chiu·S. F. Anderson·D. P. Schneider·C. J. Hogan·D. G. York·S. Burles·J. V. Brinkmann
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Abstract

The large number of quasars found in the Sloan Digital Sky Survey has allowed searches for elusive, clear lines of sight towards HeII Ly-alpha absorption, a sensitive probe of the intergalactic medium. The few known systems indicate that HeII reionization occurs at z>3. We report the detection of a HeII Ly-alpha absorption edge in a quasar spectrum at z=3.50, the most distant such feature found to date. The candidate quasar was selected from a z~3 sample in the SDSS spectroscopic quasar survey and confirmed as part of an HST/STIS SNAP survey. We discuss the general characteristics of the absorption feature, as well as the probability for discovery of additional such objects.

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W. Zheng, K. Chiu, S. F. Anderson, D. P. Schneider, C. J. Hogan, D. G. York, S. Burles, J. V. Brinkmann. 2003-11-13. Detection of Intergalactic HeII Absorption at Redshift 3.5. https://doi.org/10.1086/381485

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