论文标题
明确的上限对类星体对宇宙电离的贡献可忽略不计
Definitive upper bound on the negligible contribution of quasars to cosmic reionization
论文作者
论文摘要
宇宙（氢）的电源标志着在红移z> = 6处宇宙的主要相变之一。在此时期，lyman continuum（lyc）光子电离将氢原子（IgM）中的氢原子电离。但是，确定负责电离的LYC光子的主要来源仍然具有挑战性。特别是，类星体（或活性银河核，AGN）和星系的个人贡献仍在争论中。在这里，我们在z> = 6处构建了1类品类品类的远图（FAR-UV）光度函数，该功能跨越10个幅度（-19 <m_uv <-29），最终表明了类星体对re否做出了可忽略的贡献。我们主要在M_UV> -23 mag的低亮度范围内搜索类星体，这对于确定类星体的总LYC光子产生至关重要，但以前几乎没有探索过。我们发现，类星体种群只能提供少于7％（95％的置信度），以使宇宙保持在z = 6.0-6.6所需的总光子所需的总光子。我们的结果表明，星系，大概是低亮度的星形成系统，是氢气离子的主要来源。
Cosmic (hydrogen) reionization marks one of the major phase transitions of the universe at redshift z >= 6. During this epoch, hydrogen atoms in the intergalactic medium (IGM) were ionized by Lyman continuum (LyC) photons. However, it remains challenging to identify the major sources of the LyC photons responsible for reionization. In particular, individual contributions of quasars (or active galactic nuclei, AGNs) and galaxies are still under debate. Here we construct the far-ultraviolet (far-UV) luminosity function for type 1 quasars at z >= 6 that spans 10 magnitudes (-19 < M_UV < -29), conclusively showing that quasars made a negligible contribution to reionization. We mainly search for quasars in the low-luminosity range of M_UV > -23 mag that is critical to determine quasars' total LyC photon production but has been barely explored previously. We find that the quasar population can only provide less than 7% (95% confidence level) of the total photons needed to keep the universe ionized at z = 6.0 - 6.6. Our result suggests that galaxies, presumably low-luminosity star-forming systems, are the major sources of hydrogen reionization.
