论文标题
在Z〜0.5群集的郊区发现凉爽，金属富含的气体储层
Discovery of a cool, metal-rich gas reservoir in the outskirts of z ~ 0.5 clusters
论文作者
论文摘要
我们构建了有史以来第一个具有统计学意义的样本，分别是〜80,000个背景类别群集对，以研究Z〜0.5簇的郊区（> r500）中的凉爽，金属丰富的气体，中位数为〜10^14.2 m_sun。通过交叉匹配Wen＆Han（2015）和Lyke等人的SDSS类星体目录来获得样品。 （2020）。来自类星体视线的簇的中值冲击参数（RHO_CL）为2.4 MPC（中间RHO_CL/R500 = 3.6）。强烈的MGII以及边缘FEII，在数量的平均值和中位堆叠光谱中检测到，总MGII REST式等效宽度（W^（2796+2803））为0.034 PM 0.005 A（7simga）和0.010 PM 0.003 pm 0.003 A（3sig a（3sig）），相应地相应。 W^（2796+2803）显示出趋势的下降，随着RHO_CL和RHO_CL/R500的增加，但在此探测的小M500和ZCL范围内质量（M500）或RedShift（ZCL）并未显示出任何明显的趋势。即使我们排除了背景类星体可能正在探测效果<300 kpc的明亮星系的圆周循环培养基（CGM），MGII吸收信号和趋势仍然存在。此处报告的MGII（和FEII）吸收是对同类的第一次检测。它表明存在周围银河系簇的凉爽，金属富含气体的储层，直至几r500。我们建议，集群郊外的金属富含气体是由剥离的材料产生的，而气体剥离可能对大型中心距离（> 3R500）很重要。
We built the first-ever statistically significant sample of ~ 80,000 background quasar - foreground cluster pairs to study the cool, metal-rich gas in the outskirts (> R500) of z ~ 0.5 clusters with a median mass of ~ 10^14.2 M_sun. The sample was obtained by cross-matching the SDSS cluster catalog of Wen & Han (2015) and SDSS quasar catalog of Lyke et al. (2020). The median impact parameter (rho_cl) of the clusters from the quasar sightlines is 2.4 Mpc (median rho_cl/R500 = 3.6). A strong MgII, along with marginal FeII, absorption is detected in the mean and median stacked spectra of the quasars with total MgII rest-frame equivalent width (W^(2796+2803)) of 0.034 pm 0.005 A (7simga) and 0.010 pm 0.003 A (3sigma), respectively. The W^(2796+2803) shows a declining trend with increasing rho_cl and rho_cl/R500, but does not show any significant trend with mass (M500) or redshift (zcl) within the small M500 and zcl ranges probed here. The MgII absorption signal and the trends persist even if we exclude the quasar-cluster pairs where the background quasars may be probing the circum-galactic medium (CGM) of bright galaxies with impact parameters < 300 kpc. The MgII (and FeII) absorption reported here is the first detection of its kind. It indicates the presence of a cool, metal-rich gas reservoir surrounding galaxy clusters out to several R500. We suggest that the metal-rich gas in the cluster outskirts arise from stripped materials and that gas stripping may be important out to large clustocentric distances (> 3R500 ).
