Advances in Astronomy and Space Physics, Volume 6, Issue 1, PP. 34-40 (2016)
doi: 10.17721/2227-1481.6.34-40

Influence of the continuum determination method
on the mean transmission in the Lyα forest

O. Torbaniuk

Main Astronomical Observatory of the NAS of Ukraine, 27 Akademika Zabolotnoho Str., Kyiv 03680, Ukraine

Abstract
Determination of the initial flux, or continuum, in the quasar spectra prior to its absorption by the intergalactic HI is nontrivial problem and it affects the precision of the mean transmission in the Lyα forest, <F>(z). The results of comparison of the <F>(z) values obtained using different methods of the continuum determination are presented in this paper. This analysis was conducted using the most complete compilation of the <F>(z) data from the literature. It was found that the values of the <F>(z) obtained with the manually determined continuum are systematically higher than those obtained from extrapolated continuum. The difference varies from 5% at z=2 up to 33% at z=4.5, respectively.

Keywords:
quasars: absorption lines, methods: data analysis, statistical, large-scale structure of Universe