@article{oai:ir.soken.ac.jp:00003300, author = {池内, 了 and DENDA, Kiyomi and IKEUCHI, Satoru}, issue = {5}, journal = {Publications of the Astronomical Society of Japan, Publications of the Astronomical Society of Japan}, month = {}, note = {application/pdf, In order to examine the line-blanketing effect due to gaseous clouds at high redshifts, we have calculated the ionization states of gas clouds of subgalactic mass scale exposed to a UV radiation field that can reproduce the ionization states of the Lyman limit systems (LLSs) along the line of sight to quasar HS1700+6416. We also adopted the integrated UV radiation from the observed quasars modified by the intervening absorption due to the Lyman alpha forest and LLSs as an ionizing spectrum. Our photoionization models can explain the observed HI column-density distribution, the observed CIV/HI ratio and the observed optical depths of HI and HeII. We conclude that the integrated UV background models can well explain the ionization states of both the IGM and Lyman alpha clouds at z ~ 2--3. The gaseous mass of the Lyman alpha clouds follows a power-law form as dn/dM_c ~ M_c(-delta ) with delta ~ 2--2.5 in the 10(8) --10(11) MO range. The majority of the dark baryon probably consists of the IGM.}, pages = {639--655}, title = {Intergalactic absorption due to extended gaseous clouds at high redshifts}, volume = {48}, year = {1996} }