The Massive and Distant Clusters of WISE Survey 2: A Stacking Analysis Investigating the Evolution of Star Formation Rates and Stellar Masses in Groups and Clusters
A. Trudeau, Anthony H. Gonzalez, K. Thongkham, Kyoung-Soo Lee, Stacey Alberts, M. Brodwin, Thomas Connor, Peter R. M. Eisenhardt, Emily Moravec, Eshwar Puvvada, S. A. Stanford
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22 pages, 14 figures, accepted for publication in ApJ (corrected Popescu et al., 2023 sSFR on Figure 14)
The evolution of galaxies depends on their masses and local environments; understanding when and how environmental quenching starts to operate remains a challenge. Furthermore, studies of the high-redshift regime have been limited to massive cluster members, owing to sensitivity limits or small fields of views when the sensitivity is sufficient, intrinsically biasing the picture of cluster evolution. In this work, we use stacking to investigate the average star formation history of more than 10,000 groups and clusters drawn from the Massive and Distant Clusters of WISE Survey 2 (MaDCoWS2). Our analysis covers near ultraviolet to far infrared wavelengths, for galaxy overdensities at $0.5 \lesssim z \lesssim 2.54$. We employ SED fitting to measure the specific star formation rates (sSFR) in four annular apertures with radii between 0 and 1000 kpc. At $z \gtrsim 1.6$, the average sSFR evolves similarly to the field in both the core and the cluster outskirts. Between $\overline{z} = 1.60$ and $\overline{z} = 1.35$, the sSFR in the core drops sharply, and continues to fall relative to the field sSFR at lower redshifts. We interpret this change as evidence that the impact of environmental quenching dramatically increases at $z \sim 1.5$, with the short time span of the transition suggesting that the environmental quenching mechanism dominant at this redshift operates on a rapid timescale. We find indications that the sSFR may decrease with increasing host halo mass, but lower-scatter mass tracers than the signal-to-noise ratio (S/N) are needed to confirm this relationship.
Interferometric Cubelet Stacking to Recover H\,\textsc{i} Emission from Distant Galaxies
本文介绍了一种在红移21 cm H，\textsc{i}线上叠加星系干涉测量数据立方体的方法。与传统的光谱叠加技术，堆叠一维光谱提取的数据立方体，我们研究了一种方法，基于图像域堆栈，使反卷积成为可能。为了验证这一假设的有效性，我们模拟了一个样本的3622赤道星系提取的GAMA调查，最近成像的DINGO-VLA项目的一部分。我们首先使用无噪声模拟检查该方法的准确性，并注意到与传统堆叠相比，堆叠图像和通量估计得到了显着改善。从去卷积图像中提取的H1，\textsc{i}质量与平均输入质量一致，在3%以内。然而，利用传统的谱叠加，导出的H1，\textsc{i}不正确，不正确的系数大于2。对于一个更现实的情况下，堆栈与有限的S/N，我们还产生了20个不同的噪声实现密切模仿的DINGO-VLA干涉测量的属性。我们将预测的平均H\，\textsc{i}质量恢复到$\sim$ 4\%以内。与传统的光谱叠加技术相比，该技术扩展了叠加技术的科学应用范围，特别适用于用干涉仪表征扩展源的辐射。
A search for HI absorption in distant star-forming galaxies with ASKAP-FLASH - II. Direct observations and stacking of 21 cm line
E. A. Milne Centre for Astrophysics, University of Hull（赫尔大学 E.A. 米尔天体物理中心）；Sydney Institute for Astronomy, School of Physics A28, University of Sydney（悉尼大学物理学院A28悉尼天文研究所）；ATNF, CSIRO Space and Astronomy（CSIRO空间与天文台顶射电天文）；ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D)（ARC三维全天空天体物理学卓越中心 (ASTRO 3D)）；School of Chemical and Physical Sciences, Victoria University of Wellington（惠灵顿维多利亚大学化学与物理科学学院）；Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester（曼彻斯特大学物理与天文学院乔德雷尔银行天体物理中心）；United Kingdom SKA Regional Centre (UKSRC), University of Manchester（曼彻斯特大学英国SKA区域中心 (UKSRC)）；ASTRON – Netherlands Institute for Radio Astronomy（荷兰射电天文研究所 ASTRON）
The Massive and Distant Clusters of WISE Survey 2: Detection of splashback radii in galaxy cluster total light stacks
Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；Department of Astronomy, University of Florida（佛罗里达大学天文学系）；National Astronomical Research Institute of Thailand (NARIT)（泰国国家天文研究所）；Korea Astronomy and Space Science Institute（韩国天文与空间科学研究所）；Eureka Scientific（尤里卡科学公司）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）
Deep X-ray View of a Distant Protocluster Anchored by a Quasar at $z=6.63$: No Evidence for Enhanced X-ray AGN Activity
Peking University（北京大学）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Nanjing University（南京大学）；University of Michigan（密歇根大学）
Cluster kinematics and stellar rotation in NGC 419 with MUSE and adaptive optics
我们提出了自适应光学（AO）辅助的小麦哲伦云中的中间年龄星团NGC 419的积分场光谱。通过研究主序星（MSTO）的星团动力学和旋转特性，我们证明了AO馈MUSE观测这类天体的能力。基于1049个径向速度测量结果，我们确定了星团的动态质量为1.4+/-0.2x10^5 M_sun，动态质光比为0.67+/-0.08，略高于Kroupa初始质量函数的简单恒星星族预测。在扩展的MSTO两侧的光谱的堆叠分析显示显着的旋转增宽。我们的分析进一步提供了初步证据，证明红色MSTO恒星的旋转速度比蓝色恒星快。我们发现蓝色和红色MSTO恒星的平均V sin i值分别为87+/-16 km/s和130+/-22 km/s。由于MUSE的低光谱分辨率，潜在的系统效应可达30 km/s，但种群之间的V sin i差异不太可能受到影响。
