Projected distances to host galaxy reduce SNIa dispersion
R. Hill, H. Shariff, R. Trotta, S. Ali-Khan, X. Jiao, Y. Liu, S. K. Moon, W. Parker, M. Paulus, D. A. van Dyk, L. B. Lucy
备注：
Major revision including new fits to the host galaxy images and checks of robustness of results. Statistical results are strengthened. Matched version accepted by MNRAS
我们使用斯隆数字巡天（SDSS）的多波段图像数据来测量302个Ia型超新星（SNIa）从其宿主星系中心的投影距离，归一化到星系的亮度标度长度，采用贝叶斯方法。我们测试的假设，SNIas远离他们的宿主星系的中心较少受到尘埃污染（在他们的环境中的尘埃柱密度较小）和/或来自一个更均匀的环境。使用Mann-Whitney U检验，我们发现在靠近和远离其主机中心的SNIas之间观察到的颜色校正分布存在统计学显著差异。局部p值为3 x 10^{-3}，经别处效应校正后，在5%水平上具有显著性。我们估计两个亚组的剩余离散度为0.073 +/- 0.018，远SNIas为0.114 +/- 0.009，近SNIas为0.114 +/- 0.009--提高了30%，尽管统计学显著性较低，为2sigma。这证实了宿主星系的性质在正确解释SNIa观测宇宙学推论中的重要性。
英文摘要：
We use multi-band imagery data from the Sloan Digital Sky Survey (SDSS) to measure projected distances of 302 supernova type Ia (SNIa) from the centre of their host galaxies, normalized to the galaxy's brightness scale length, with a Bayesian approach. We test the hypothesis that SNIas further away from the centre of their host galaxy are less subject to dust contamination (as the dust column density in their environment is smaller) and/or come from a more homogeneous environment. Using the Mann-Whitney U test, we find a statistically significant difference in the observed colour correction distribution between SNIas that are near and those that are far from the centre of their host. The local p-value is 3 x 10^{-3}, which is significant at the 5 per cent level after look-elsewhere effect correction. We estimate the residual scatter of the two subgroups to be 0.073 +/- 0.018 for the far SNIas, compared to 0.114 +/- 0.009 for the near SNIas -- an improvement of 30 per cent, albeit with a low statistical significance of 2sigma. This confirms the importance of host galaxy properties in correctly interpreting SNIa observations for cosmological inference.
The Pantheon+ Analysis: Forward-Modeling the Dust and Intrinsic Colour Distributions of Type Ia Supernovae, and Quantifying their Impact on Cosmological Inferences
Statistics of the projected angles between the black-hole spin and the host-galaxy rotation axes from NewHorizon
ILANCE, CNRS – University of Tokyo International Research Laboratory（ILANCE，CNRS-东京大学国际研究实验室）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（卡弗里宇宙物理学与国际前沿研究中心（WPI），UTIAS，东京大学）；Department of Physics, School of Science, The University of Tokyo（东京大学理学部物理系）；Research Institute, Kochi University of Technology（高知工科大学研究所）；Co-creation Organization of Regional Innovation, Kochi University of Technology（高知工科大学区域创新共创组织）；Institut d’Astrophysique de Paris, CNRS and Sorbonne Université（巴黎天体物理研究所，CNRS和索邦大学）；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 and Yonsei University Observatory, Yonsei University（延世大学天文系及延世大学天文台）
When Streams Curve Away: a Test of Dark Matter from Extragalactic Stellar Stream Populations
Massachusetts Institute of Technology（麻省理工学院）；Case Western Reserve University（凯斯西储大学）；Princeton University（普林斯顿大学）；Technical University of Denmark（丹麦技术大学）；University of Copenhagen（哥本哈根大学）
Exploring galaxy dark matter halos across redshifts with strong quasar absorbers
类星体的视线相交干预星系盘或环银河系的环境在随机的碰撞参量和潜在的井深。已知吸收线速度宽度（$Δv_{90}$）与宿主星系的恒星质量成比例，与类星体视线的投影距离成反比。它对恒星质量的依赖性可以通过与宿主星系的发射线宽度$σ_{em}$归一化来消除，因此可以直接比较具有$Δv_{90}$值范围的吸收体。利用一个在0.2 < z < 3.2的DLA系统的样本，我们发现，速度比$Δv_{90}/σ_{em}$与主机的投影距离减小。我们比较的数据与预期的视线速度分散来自不同的暗物质晕质量分布，并发现模型与陡峭的径向暗物质配置文件提供了一个更好的拟合的意见，虽然散射仍然很大。从星系流出的气体可能会导致散射增加，或者暗物质晕模型的尺度半径可能不代表星系。通过计算维里速度，我们证明了属于大质量星系晕（M $_{halo} \approx 10^{12}$ M $_{\odot}$）的富含金属的DLAs大部分仍然受引力束缚在晕上。
Search for quasar pairs with Gaia astrometric data IV. Confirmation of 17 dual quasars and 143 projected quasars
School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿交叉科学研究院）
