Imaging of diffuse H I absorption structure in the SSA22 protocluster region at z = 3.1
Imaging of diffuse H I absorption structure in the SSA22 protocluster region at z = 3.1
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SSA22 原星团区域 z = 3.1 处弥散 H I 吸收结构的成像
DOI：
10.1093/mnras/stx038
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Ken Mawatari et al.
中科院分区：
文献类型：
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作者：
Umehata;H.; Matsuda;Y.; Tamura;Y.; Kohno;K.; Smail;I.; Ivison;R. J.; Steidel;C. C.; Chapman;S. C.; Geach;J. E.; Hayes;M.; Nagao;T.; Ao;Y.; Kawabe;Y.; Yun;M. S.; Hatsukade;B.; Kubo;M.; Kato;Y.; Saito;T.; Ikarashi;S.; Nakanishi;K.; Lee;Yusuke Nakamura;Zhiyuan Li;Ken Mawatari et al.
使用星系作为背景光源来绘制干预 Ly α 吸收图是研究星系、环星系介质 (CGM) 和星系间介质之间相互作用的一种新方法。引入相对于宇宙平均值的 z= 3.1 HiLy α 吸收的新测量值 ΔNB497（根据 3.3 ≲z≲ 3.5 处恒星形成星系的光度数据估计），我们在 z= 3.1 SSA22 原星系团区域和两个控制场（Subaru/XMM-NewtonDeep Survey；大天文台光学）中制作了二维 ΔNB497 地图Deep Survey North），空间分辨率为 ∼5 comoving Mpc。 SSA22 区域中的 ΔNB497 测量值总体上大于对照区域中的测量值，并且这种 Hiab 年 吸增强扩展了超过 50 个共动 Mpc。场平均（即〜50共动Mpc尺度）ΔNB497和Lyα发射器（LAE）的超密度似乎是相关的，而在一些共动Mpc尺度中，ΔNB497对局部LAE超密度没有明显的依赖性。这些结果表明，弥散的 Higas 在 SSA22 原星团内部/周围扩散。我们还发现，至少在 SSA22 场中，距最近的 z= 3.1 星系的投影距离 <100 物理 kpc 处 ΔNB497 有所增强，这可能是由于与各个星系的 CGM 相关的 Higas 所致。在 Lyα 发射较强的星系周围，CGM 尺度的 Hi 吸收增强往往较弱，这表明星系的 Lyα 逃逸分数取决于 CGM 中的氢中性。
Using galaxies as background light sources to map intervening Ly α absorption is a novel approach to study the interplay among galaxies, the circumgalactic medium (CGM) and the intergalactic medium. Introducing a new measure ofz= 3.1 HiLy α absorption relative to the cosmic mean, ΔNB497, estimated from photometric data of star-forming galaxies at 3.3 ≲z≲ 3.5, we have made two-dimensional ΔNB497 maps in thez= 3.1 SSA22 protocluster region and two control fields (Subaru/XMM–NewtonDeep Survey; Great Observatory Optical Deep Survey North) with a spatial resolution of ∼5 comoving Mpc. The ΔNB497 measurements in the SSA22 field are systematically larger than those in the control fields, and this Hiabsorption enhancement extends more than 50 comoving Mpc. The field-averaged (i.e. ∼50 comoving Mpc scale) ΔNB497 and the overdensity of Ly α emitters (LAEs) seem to be correlated, while there is no clear dependency of the ΔNB497 on the local LAE overdensity in a few comoving Mpc scale. These results suggest that diffuse Higas spreads out in/around the SSA22 protocluster. We have also found an enhancement of ΔNB497 at a projected distance <100 physical kpc from the nearestz= 3.1 galaxies at least in the SSA22 field, which is probably due to Higas associated with the CGM of individual galaxies. The Hiabsorption enhancement in the CGM-scale tends to be weaker around galaxies with stronger Ly α emission, which suggests that the Ly α escape fraction from galaxies depends on hydrogen neutrality in the CGM.