文章基本信息

标题：Effective Opacity of the Intergalactic Medium from Galaxy Spectra Analysis
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作者：Jose S.Monzon ; J.Xavier Prochaska ; Khee-Gan Lee 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2020
卷号：160
期号：1
页码：1-12
DOI：10.3847/1538-3881/ab94c2
语种：English
出版社：American Institute of Physics
摘要：We measure the effective opacity (${\tau }_{\mathrm{eff}}$) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2 lesssim z lesssim 3. Our spectra are taken from the COSMOS Lyα Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We generate composite spectra in two redshift intervals and fit them with spectral energy distribution (SED) models composed of simple stellar populations. Extrapolating these SED models into the Lyα forest, we measure the effective Lyα opacity (${\tau }_{\mathrm{eff}}$) in the 2.02 ≤ z ≤ 2.44 range. At z = 2.22, we estimate ${\tau }_{\mathrm{eff}}\,=0.159\pm 0.001$ from a power-law fit to the data. These measurements are consistent with estimates from quasar analyses at z < 2.5 indicating that the systematic errors associated with normalizing quasar continua are not substantial. We provide a Gaussian processes model of our results and previous ${\tau }_{\mathrm{eff}}$ measurements that describes the steep redshift evolution in ${\tau }_{\mathrm{eff}}$ from z = 1.5–4.
关键词：Intergalactic medium (813);Intergalactic gas (812);Lyman-break galaxies (979)