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FUSE observations of the HeII Lyman alpha forest towards HS1700+6416

D. Reimers·C. Fechner·G. Kriss·M. Shull·R. Baade·W. Moos·A. Songaila·R. Simcoe
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Abstract

We present FUSE observations of the HeII Lyman alpha forest in the redshift range 2.3 < z < 2.7 towards HS1700+6416. Between October 2002 and February 2003, the brightness of the QSO increased by a factor 2. Therefore, with an exposure time of 203 ks during orbital night, the quality of the resulting spectrum is comparable to the HE2347-4342 data. This second line of sight with a resolved HeII Lyman alpha forest reveals a similar variation of several orders of magnitude of the column density ratio eta = N(HeII)/N(HI) and confirms the results of previous studies. The well-known metal line spectrum of HS1700+6416 permits to examine the influence of metal line absorption on the HeII column densities.

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D. Reimers, C. Fechner, G. Kriss, M. Shull, R. Baade, W. Moos, A. Songaila, R. Simcoe. 2004-10-25. FUSE observations of the HeII Lyman alpha forest towards HS1700+6416. https://arxiv.org/abs/astro-ph/0410588

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