Equilibrium axisymmetric halo model for the Milky Way and its implications for direct and indirect DM searches
Mihael Petac
备注:
Article consists of 44 pages, 15 figures. We additionally provide the tabulated values of astrophysical factors (in total 18 files) obtained in this work
We for the first time provide self-consistent axisymmetric phase-space distribution models for the Milky Way's dark matter (DM) halo which are carefully matched against the latest kinematic measurements through Bayesian analysis. By using broad priors on the individual galactic components, we derive conservative estimates for the astrophysical factors entering the interpretation of direct and indirect DM searches. While the resulting DM density profiles are in good agreement with previous studies, implying $ρ_\odot \approx 10^{-2} \, M_\odot / \mathrm{pc}^3$, the presence of baryonic disc leads to significant differences in the local DM velocity distribution in comparison with the standard halo model. For direct detection, this implies roughly 30% stronger cross-section limits at DM masses near detectors maximum sensitivity and up to an order of magnitude weaker limits at the lower end of the mass range. Furthermore, by performing Monte-Carlo simulations for the upcoming DARWIN and DarkSide-20k experiments, we demonstrate that upon successful detection of heavy DM with coupling just below the current limits, the carefully constructed axisymmetric models can eliminate bias and reduce uncertainties by more then 50% in the reconstructed DM coupling and mass, but also help in a more reliable determination of the scattering operator. Furthermore, the velocity anisotropies induced by the baryonic disc can lead to significantly larger annual modulation amplitude and sizable differences in the directional distribution of the expected DM-induced events. For indirect searches, we provide the differential $J$-factors and compute several moments of the relative velocity distribution that are needed for predicting the rate of velocity-dependent annihilations. However, we find that accurate predictions are still hindered by large uncertainties regarding the DM distribution near the galactic center.
Axisymmetric Jeans modelling systematically overestimates the circular speed in the inner Milky Way
Graduate School of Science and Engineering, Kagoshima University(鹿儿岛大学理工学研究科);Graduate School of Science, Nagoya University(名古屋大学理学研究科);Division of Science, National Astronomical Observatory of Japan(日本国立天文台理学区)
Kinematic-Distance Biases in the Inner Milky Way from a Stellar-Dynamically Constrained Bar
Amanogawa Galaxy Astronomy Research Center, Graduate School of Science and Engineering, Kagoshima University(鹿儿大学理工学研究科银河天文研究中心);Division of Science, National Astronomical Observatory of Japan(日本国立天文台理学科)
The Milky Way's dark matter halo appears to be lopsided
银河系外围区域(距中心约10 kpc)的氢原子盘可以提供有关暗物质晕结构的有价值的信息。最近来自全天21厘米线LAB测量的外HI盘的3-D厚度图为我们提供了一个独特的机会来详细研究银河系暗物质晕的结构。这项新调查的一个显著特点是原子氢气体厚度图的南北不对称性。假设在银河系总势能下垂直流体静力平衡,我们导出了HI气体的模型厚度图。我们指出,简单的轴对称晕模型,如软化的等温晕(在Vc ~ 220 km/s处产生平坦的旋转曲线)或任何密度下降快于等温晕的晕,都不能解释所观测到的气体厚度的径向变化。我们还表明,这种轴对称晕随着不同的HI速度分散在两半,不能解释所观察到的厚度图中的不对称性。其中的非轴对称模型,它表明,一个纯粹的不平衡(m=1,第一谐波)暗物质晕合理HI速度色散未能解释南北不对称令人满意。然而,我们发现,通过在一个完全不平衡的晕上叠加一个二次谐波(m=2),例如我们的最佳拟合和更可接受的模型A(参数ε h ^{1}=0.2,ε h ^{2}=0.18,σ HI =8.5 km/s),可以提供一个很好的拟合,并自然地再现南北不对称性。新出现的不对称暗物质晕的图像得到了宇宙学N体模拟中形成的ΛCDM晕的支持。
Bar-Informed Kinematic-Distance Mapping of Molecular Gas in the Inner Milky Way
Amanogawa Galaxy Astronomy Research Center, Graduate School of Science and Engineering, Kagoshima University(鹿儿大学理工学研究科银河天体物理研究中心);Division of Science, National Astronomical Observatory of Japan(日本国立天文台理学院)
Orbits of 152 Globular Clusters of the Milky Way Galaxy Constructed from the Gaia DR2 data
我们介绍了银河系152个球状星团的轨道及其性质,这些星团是使用Vasiliev(2019)列表中的平均Gaia DR 2自行和其他天体测量数据获得的。对于轨道积分,我们使用了基于Navarro-Frenk-White暗晕的银河势的轴对称模型,并由Bajkova和Bobylev(2016)使用Bhattacharjee et.al.(2014)目录中银河系天体在银河系中心距离的广泛区域(高达200 kpc)的圆速度进行了修改。在对所得到的轨道进行分析的基础上,我们修正了Massari等人提出的球状星团子系统的组成。(2019).
Effective $J$-factors for Milky Way dwarf spheroidal galaxies with velocity-dependent annihilation
我们计算的有效$J$ -因素,这决定了暗物质湮灭的间接检测信号的强度,为25矮球状星系(dSphs)。我们考虑几个动机良好的假设的相对速度依赖的暗物质湮灭截面:$σ_A v$:$s$ -波(速度无关),$p$ -波($σ_A v \propto v^2$),$d$ -波($σ_A v \propto v^4$),和Sommercun增强库仑极限($σ_A v \propto 1/v$)。因此,我们提供了最大的和最新的样本的J-因子的速度相关的湮灭模型。对于每种情况下,我们使用费米-LAT伽马射线数据来约束湮灭截面。由于在我们的伽马射线数据分析的假设,我们的界限是可比的$p$波和Sommerdos增强截面使用dSphs上的以前的界限。我们的界限上的$d$波截面是第一个这样的界限使用间接检测数据。
Galactic tides in the Solar System within a non-axisymmetric Milky Way model adjusted to Gaia data
Université PSL, Sorbonne Université, Université de Lille(巴黎文理研究大学、索邦大学、里尔大学);Università degli Studi di Firenze(佛罗伦萨大学);Université de Strasbourg(斯特拉斯堡大学);Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université(巴黎天文台、巴黎文理研究大学、索邦大学、巴黎西岱大学、塞吉-蓬图瓦兹大学)
Kinematic characteristics of the Milky Way globular clusters based on Gaia DR2 data
利用Gaia(ESA)Data Release 2的数据,对银河系中的球状星团(GCs)进行了轨道计算。为了探索GC之间可能的近距离接触(或碰撞),使用我们自己开发的高阶phi-GRAPE代码,我们向后和向前整合了119个具有可靠位置和自行的物体的轨道。在计算中,我们采用了一个现实的轴对称银河势(球+盘+晕)。使用不同的撞击条件,我们发现了六个GC中的四对可能在过去5Gyr的半质量半径(碰撞)之和的两倍内经历了一次相遇:Terzan 3- NGC 6553,Terzan 3 - NGC 6218,Liller 1 - NGC 6522和Djorg 2 - NGC 6553。
Self-consistent modelling of the Milky Way's Nuclear Stellar Disc
Universität Heidelberg(海德堡大学);University College London(伦敦大学学院);University of Cambridge(剑桥大学);University of Virginia(弗吉尼亚大学);Max-Planck-Institut fur Extraterrestrische Physik(马克斯·普朗克地外物理研究所);Instituto de Astrofisica de Andalucia (CSIC)(安达卢西亚天体物理学研究所(西班牙国家科学研究委员会));Rudolf Peierls Centre for Theoretical Physics(鲁道夫·派尔斯理论物理中心);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Lund Observatory(隆德天文台)
Università dell’Insubria(因苏布里亚大学);University of Malta(马耳他大学);University of Lancashire(兰开夏大学);Instituto de Astrofísica de Andalucía (CSIC)(安达卢西亚天体物理研究所(西班牙高等科研理事会));University College London(伦敦大学学院);Université Côte d’Azur(蔚蓝海岸大学)
A Self-Consistent Jeans Analysis of the Milky Way Rotation Curve
Tsinghua University(清华大学);LIRA, Observatoire de Paris, Université PSL, CNRS(巴黎天文台 LIRA 实验室,巴黎大学,法国国家科学研究中心);Center for Astronomy, Space Science and Astrophysics, Independent University, Bangladesh(孟加拉独立大学天体物理学、空间科学与天文学中心);Local Universe and Time-Domain Astronomy Laboratory, Department of Astronomy, China West Normal University(西华师范大学天文学院本地宇宙与时域天文实验室)