斯皮策适应性红序星系团巡天（SpARCS）是对50度^2斯皮策SWIRE遗留磁场的z '通带成像巡天，其主要目的是创建第一个z>1的大质量星系团的大型均匀选择样本。SpARCS使用红外适应的两个过滤器集群红色序列技术。在这篇论文中，我们报告了两个新的异常丰富的星系团的Keck/LRIS光谱确认，SpARCS J161315+564930，z=0.871+/-0.002，有14个高置信度成员，静止帧速度色散为sigma_v= 1230+/-320 km s^-1，和SpARCS J161641+554513，z=1.161+/-0.003，有7个高置信度成员（包括一个活动星系核），静止坐标系速度色散σ_v=950+/-330 km s^-1。我们还确认了第三个新系统，SpARCS J161037+552417，z=1.210+/-0.002，有7个高置信度成员，静止坐标系速度离散为sigma_v=410+/-300 km s^-1。这三个新的光谱证实的集群进一步证明了效率和有效性的双过滤器成像检测真正的星系团在高红移。我们的结论是，前景是好的，为当前一代的调查，旨在估计集群红移和质量在z>~1直接从光学红外成像。
英文摘要：
The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey of the 50 deg^2 Spitzer SWIRE Legacy fields, designed with the primary aim of creating the first large, homogeneously selected sample of massive clusters at z>1. SpARCS uses an infrared adaptation of the two-filter cluster red-sequence technique. In this paper we report Keck/LRIS spectroscopic confirmation of two new exceptionally rich galaxy clusters, SpARCS J161315+564930 at z=0.871+/-0.002, with 14 high-confidence members and a rest-frame velocity dispersion of sigma_v= 1230+/-320 km s^-1, and SpARCS J161641+554513 at z=1.161+/-0.003, with seven high-confidence members (including one AGN) and a rest-frame velocity dispersion of sigma_v=950+/-330 km s^-1. We also report confirmation of a third new system, SpARCS J161037+552417 at z=1.210+/-0.002, with seven high-confidence members and a rest-frame velocity dispersion of sigma_v=410+/-300 km s^-1. These three new spectroscopically confirmed clusters further demonstrate the efficiency and effectiveness of two-filter imaging for detecting bona fide galaxy clusters at high redshift. We conclude by demonstrating that prospects are good for the current generation of surveys aiming to estimate cluster redshifts and masses at z>~1 directly from optical-infrared imaging.
In the hierarchical structure formation model of the universe, galaxy clusters are assembled through a series of mergers. Accordingly, it is expected that galaxy clusters in the early universe are actively forming and dynamically young. Located at a high redshift of z=1.71, SpARCS1049+56 offers a unique look into the galaxy cluster formation process. This cluster has been shown to be rich in cluster galaxies and to have intense star formation. Its high redshift pushes a weak-lensing analysis beyond the regime of the optical spectrum into that of the infrared. Equipped with deep Hubble Space Te…
We present a comparison of two samples of z>0.8 galaxy clusters selected using different wavelength-dependent techniques and examine the physical differences between them. We consider 18 clusters from the X-ray selected XMM-LSS distant cluster survey and 92 clusters from the optical-MIR selected SpARCS cluster survey. Both samples are selected from the same approximately 9 square degree sky area and we examine them using common XMM-Newton, Spitzer-SWIRE and CFHT Legacy Survey data. Clusters from each sample are compared employing aperture measures of X-ray and MIR emission. We divide the SpARC…
The eROSITA Final Equatorial-Depth Survey (eFEDS), covering ~140 square degrees, was performed as part of the performance verification phase of the eROSITA telescope on board of the Russian-German satellite Spectrum-Roentgen-Gamma (SRG). In this paper we present the optical follow-up of 542 X-ray extent selected galaxy group and cluster candidates providing redshifts and cluster confirmation for the full sample. We use optical imaging data from the Hyper Suprime-Cam Subaru Strategic Program and from the Legacy Survey to run the cluster redshift and confirmation tool MCMF as well as the optical…
We present MMT spectroscopic observations of two massive galaxy cluster candidates at redshift $z\sim0.07$ that show extended and diffuse X-ray emission in the ROSAT All Sky Survey (RASS) images. The targets were selected from a previous catalog of 303 newly-identified cluster candidates with the similar properties using the intra-cluster medium emission. Using the new MMT Hectospec data and SDSS archival spectra, we identify a number of member galaxies for the two targets and confirm that they are galaxy clusters at $z=0.079$ and 0.067, respectively. The size of the two clusters, calculated f…
Spectroscopic confirmation of z~7 LBGs: probing the earliest galaxies and the epoch of reionization
我们在ESO/VLT上展示了FORS 2超深光谱活动的最终结果，以确认从我们的VLT/Hawk-I成像调查中选择的三个独立领域的z~7“z-波段脱落”候选者。我们特别报道了在NTT深场中新发现的两个红移约为6.7的星系：这两个星系都显示出Ly-alpha发射线，其静止坐标系EW为15-20 A量级，光度为2-4 X 10^{42} erg/s。我们还提出了一个样本的i-dropout星系的超深观测的结果，从中我们设置了一个坚实的上限的分数的闯入者。在观察到的20个z-dropout中，我们确认了5个星系在6.7 < z < 7.1。这系统地低于根据较低红移观测得出的预期：特别是有一个显着缺乏对象与中间Ly-alpha EW（20和55 A之间）。我们的结论是LBG中Ly-alpha发射的分数从z~3到z~6不断增加的趋势很可能从z~6到z~7反转。解释观测到的LAE分数在辍学人口与再电离之间的快速变化需要一个快速演变的中性部分的氢在宇宙中。假设宇宙在z=6时完全电离，并采用Dijkstra et al.（2011）的半解析模型，我们发现我们的数据要求中性氢分数在时间Δ z ~ 1内发生Δ chi_{HI} ~ 0.6量级的变化，前提是逃逸分数在相同的红移间隔内没有显著增加。
Keck/LRIS Spectroscopic Confirmation of Coma Cluster Dwarf Galaxy Membership Assignments
Keck/LRIS多目标光谱仪对后发座星系团核心区的140个最低和最高表面亮度的暗（19 < R < 22）矮星系候选者进行了测量。这些光谱被用来测量红移，并建立这些微弱的矮种群的成员资格。低表面亮度样本的主要目标是测试我们使用形态和表面亮度标准区分后发座星系团成员和背景星系的能力，使用高分辨率HST/ACS图像。候选人被评为预期成员，不确定，或预期的背景。从93个光谱中识别出51个矮星系成员和20个背景星系。我们的形态成员估计成功率为100%的对象，预计将成为成员和优于90%的星系预计将在背景中。我们确认，低表面亮度是一个很好的指标集群成员。高表面亮度星系几乎总是背景与混乱所产生的情况下，只有罕见的紧凑的椭圆星系。在中等表面亮度下出现更多问题的情况。这些星系中的许多都被赋予了不确定的成员评级，并且这些星系被发现是成员的时间约为一半。包括颜色信息将改进成员资格确定，但是对于在仅使用表面亮度和形态标准时已经被错误识别的一些相同对象将失败。具有B-V色的紧凑椭圆星系，特别是红色序列红向0.2等，需要光谱跟踪。在47个高表面亮度的样本中，有19个物体的红移使它们位于后发座星系团中。红移测量和使用间接手段建立集群成员进行了讨论。
The NIKA2 Sunyaev-Zel'dovich Large Program (SZLP) is focused on mapping the thermal SZ signal of a representative sample of selected Planck and ACT clusters spanning the redshift range 0.5<$z$<0.9. Hydrodynamical N-body simulations prove to be a powerful tool to endorse NIKA2 capabilities for estimating the impact of IntraCluster Medium (ICM) disturbances when recovering the pressure radial profiles. For this goal we employ a subsample of objects, carefully extracted from the catalog "Marenostrum MUltidark SImulations of galaxy Clusters" (MUSIC), spanning equivalent redshift and mass ranges as…
Weak-lensing Shear-Selected Galaxy Clusters from the Hyper Suprime-Cam Subaru Strategic Program: III. A precision cosmological sample enabled by optical confirmation
National Cheng Kung University（国立成功大学）；MIT Kavli Institute, Massachusetts Institute of Technology（麻省理工学院卡弗里宇宙学研究所）；Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理系）；Center for Frontier Science, Chiba University（千叶大学前沿科学中心）；Department of Physics, Graduate School of Science, Chiba University（千叶大学理学研究科物理学系）；RIKEN Center for Advanced Intelligence Project（理化学研究所先进智能项目中心）；Subaru Telescope, National Astronomical Observatory of Japan（昴星望远镜，日本国立天文台）；The Inter-University Centre for Astronomy and Astrophysics（大学间天体物理研究中心）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo（东京大学宇宙物质量子物理卡弗里研究所（WPI），东京大学高等研究院（UTIAS））
Galaxy clusters are the most massive virialized structures in the Universe and are formed through the gravitational accretion of matter over cosmic time. The discovery of an evolved galaxy cluster at redshift z=2, corresponding to a look-back time of 10.4 billion years, provides an opportunity to study its properties. The galaxy cluster XLSSC 122 was originally detected as a faint, extended X-ray source in the XMM Large Scale Structure survey and was revealed to be coincident with a compact over-density of galaxies with photometric redshifts of 1.9 +/- 0.2. Subsequent observations at millimetr…
DESI Strong Lens Foundry IV: Spectroscopic Confirmation of DESI Lens Candidates with VLT/MUSE
University of California, Berkeley（加州大学伯克利分校）；Gemini Observatory / NSF’s NOIRLab（吉米天文台 / 美国国家光学红外天文研究实验室）；University of San Francisco（旧金山大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Institute for Astronomy, University of Hawaii（夏威夷大学天体物理研究所）；University of Pittsburgh（匹兹堡大学）；University of California, Los Angeles（加州大学洛杉矶分校）；Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo（东京大学理化学研究所木下伽利略宇宙物质起源研究机构）
The FourStar Galaxy Evolution Survey (ZFOURGE): ultraviolet to far-infrared catalogs, medium-bandwidth photometric redshifts with improved accuracy, stellar masses, and confirmation of quiescent galaxies to z~3.5
