The cusp-core problem is one of the main challenges of the cold dark matter paradigm on small scales: the density of a dark matter halo is predicted to rise rapidly toward the center as rho ~ r^alpha with alpha between -1 and -1.5, while such a cuspy profile has not been clearly observed. We have carried out the spatially-resolved mapping of gas dynamics toward a nearby ultra-diffuse galaxy (UDG), AGC 242019. The derived rotation curve of dark matter is well fitted by the cuspy profile as described by the Navarro-Frenk-White model, while the cored profiles including both the pseudo-isothermal and Burkert models are excluded. The halo has alpha=-(0.90+-0.08) at the innermost radius of 0.67 kpc, Mhalo=(3.5+-1.2)E10 Msun and a small concentration of 2.0+-0.36. AGC 242019 challenges alternatives of cold dark matter by constraining the particle mass of fuzzy dark matter to be < 0.11E-22 eV or > 3.3E-22 eV , the cross section of self-interacting dark matter to be < 1.63 cm2/g, and the particle mass of warm dark matter to be > 0.23 keV, all of which are in tension with other constraints. The modified Newtonian dynamics is also inconsistent with a shallow radial acceleration relationship of AGC 242019. For the feedback scenario that transforms a cusp to a core, AGC 242019 disagrees with the stellar-to-halo-mass-ratio dependent model, but agrees with the star-formation-threshold dependent model. As a UDG, AGC 242019 is in a dwarf-size halo with weak stellar feedback, late formation time, a normal baryonic spin and low star formation efficiency (SFR/gas).
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；University of Victoria（维多利亚大学）；Carnegie Mellon University（卡内基梅隆大学）；University of Surrey（萨里大学）
Constraining the shape of dark matter haloes using only starlight II. Tests of the technique with objects of known gravitational potential
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Universidad Nacional del Noroeste de la Prov. de Buenos Aires, UNNOBA, CONICET（布宜诺斯艾利斯省西北国立大学，UNNOBA，CONICET）；University of Virginia（弗吉尼亚大学）
The condensation of baryons within a dark matter (DM) halo during galaxy formation should result in some contraction of the halo as the combined system settles into equilibrium. We quantify this effect on the cuspy primordial halos predicted by DM-only simulations for the baryon distributions observed in the galaxies of the SPARC database. We find that the DM halos of high surface brightness galaxies (with $Σ_{\rm eff}\gtrsim100$ $L_\odot$ pc$^{-2}$ at 3.6 $μ$m) experience strong contraction. Halos become more cuspy as a result of compression: the inner DM density slope increases with the bary…
Cusp-to-Core Transition of Dark Matter Halos across Galaxy Mass Scales
National Institute of Technology, Sendai College（仙台高等专门学校）；Astronomical Institute, Tohoku University（东北大学天文研究所）；ICRR, The University of Tokyo（东京大学宇宙线研究所）；Graduate School of Science and Technology, University of Tsukuba（筑波大学理工学研究科）；Center for Computational Sciences , University of Tsukuba（筑波大学计算科学中心）
The Formation of Ultra Diffuse Galaxies in Cored Dark Matter Halos Through Tidal Stripping and Heating
我们建议，超扩散星系（UDG）人口代表了一组卫星星系出生在$\sim10^{10}-10^{11}$ M $_\odot$晕，类似于场矮星，这遭受了显着减少，由于潮汐剥离和加热的表面亮度。这种情况下的观测动机的径向排列的后发座的UDG以及UDG丰度的显着依赖于集群质量。作为一个测试，这种形成的情况下，我们应用半解析模型描述的变化，恒星质量和半光半径的矮卫星，占据核心或尖状晕，集群subhalos在插图黑暗的模拟。这个模型的关键是模拟结果表明，核心暗物质晕的星系显着扩大在潮汐剥离和加热，而在尖状晕星系的经验有限的大小演变。我们的分析表明，人口潮汐剥离矮星系，居住在核心晕（如那些托管低表面亮度场矮星），能够重现观察到的大小和恒星质量的UDG在集群非常好。
The central density profiles in dwarf galaxy halos depend strongly on the nature of dark matter. Recently, in Malhan et al. (2021), we employed N-body simulations to show that the cuspy cold dark matter (CDM) subhalos predicted by cosmological simulations can be differentiated from cored subhalos using the properties of accreted globular cluster (GC) streams since these GCs experience tidal stripping within their parent halos prior to accretion onto the Milky Way. We previously found that clusters that are accreted within cuspy subhalos produce streams with larger physical widths and higher di…
Rotation curves of galaxies probe their total mass distributions, including dark matter. Dwarf galaxies are excellent systems to investigate the dark matter density distribution, as they tend to have larger fractions of dark matter compared to higher mass systems. The core-cusp problem describes the discrepancy found in the slope of the dark matter density profile in the centres of galaxies ($β^*$) between observations of dwarf galaxies (shallower cores) and dark matter-only simulations (steeper cusps). We investigate $β^*$ in six nearby spiral dwarf galaxies for which high-resolution CO $J=1-…
Signatures of Dark Matter Halo Expansion in Galaxy Populations
星系晕内的暗物质核心可以通过恒星形成区域的能量反馈形成：能量平衡表明，最大的核心形成效率出现在M $_{\star}\sim10^{8.5}$ M $_{\odot}$的星系中。我们表明，模型人口的星系，其中的密度分布已被修改，这样的重子反馈，是能够解释所观察到的星系速度函数和塔利-费舍尔关系显着优于一个模型，其中假设一个普遍的尖形密度分布。替代模型，即温暖的或自相互作用的暗物质，也提供了一个更好的匹配这些观察到的关系比一个通用的配置文件模型，但作出不同的预测晕密度轮廓如何随质量相比，重子反馈的情况下。我们建议，不同的核心形成机制可以区分的基础上留下的印记，他们在星系人口在很大范围内的质量。在目前的观测数据中，我们发现了重子反馈产生的核心形成的质量依赖性的预期签名的证据。
We run high resolution fully GPU N-body simulations to demonstrate that the dark matter distribution in M31 is well-fitted by a core-like profile. Rich observational data especially on the giant stellar stream provides stringent constraints on the initial conditions of our simulations. We demonstrate that accretion of a satellite on a highly eccentric orbit heats up the central parts of M31, causes an outward migration of dark matter particles, flattens the central cusp over more than a decade in scale and generates a new model-independent dark matter profile that is well-fitted by a core. Our…
In this paper, we consider the problem of the evolution of the disk subsystem of galaxies in view of the halo. To this end, we have studied the dependence of the evolution of a non-linearly non-radially disk oscillating in its plane depending on the basic parameters of the dark matter halo numerically. The dark matter halo stabilizes the instabilities in the plane of the disk, but destabilizes its vertical oscillations. The global disk structure is dependent strongly on the mass and shape of the of dark matter halo. The evolutionary dependence of the oscillation process of a self-gravitating d…
Connection between galaxy morphology and dark-matter halo structure II: predicting disk structure from dark-matter halo properties
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）；Department of Astronomy, University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校天文学系）；Carnegie Observatories（卡内基观测站）；TAPIR, California Institute of Technology（加州理工学院 TAPIR）；Center for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University（耶路撒冷希伯来大学拉卡物理学院天体物理学与行星科学中心）
The GMRT archive atomic gas survey -- III. Comparative Study of Dark Matter Halos in Nearby Galaxies
Indian Institute of Science（印度科学研究所）；Indian Institute of Astrophysics（印度天体物理研究所）；Max-Planck-Institut für Radioastronomie (MPIfR)（马克斯·普朗克射电天文研究所）；Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences（保加利亚科学院天文学与国家天文台）；New Mexico Institute of Mining and Technology（新墨西哥矿业理工学院）；Indian Institute of Technology Indore（印度印多尔理工学院）；ASTRON – Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；National Centre for Radio Astrophysics (NCRA–TIFR)（国家射电天体物理学中心）
There had been recent advancement toward the detection of ultra-faint dwarf galaxies, which may serve as a useful laboratory for dark matter exploration since some of them contains almost 99$\%$ of pure dark matter. The majority of these galaxies contain no black hole that inhabits them. Recently, there had been reports that some dwarf galaxies may have a black hole within. In this study, we construct a black hole solution combined with the Dehnen dark matter halo profile, which is commonly used for dwarf galaxies. We aim to find out whether there would be deviations relative to the standard b…
M54 is a prototype of a globular cluster embedded in a dark matter halo. Gaia EDR3 photometry and proper motions separate the old, metal-poor stars from the more metal rich and younger dwarf galaxy stars. The metal poor stars dominate the inner 50 pc, with a velocity dispersion profile that declines to a minimum around 30 pc then rises back to nearly the central velocity dispersion, as expected for a globular cluster at the center of a dark matter halo. The Jeans analysis of the three separate stellar populations give consistent masses that rise approximately linearly with radius to 1 kpc, imp…
Epicyclic Density Variations in the Indus Stellar Stream
Department of Astronomy and Astrophysics, University of Toronto（多伦多大学天文与天体物理系）；Dunlap Institute for Astronomy & Astrophysics, University of Toronto（多伦多大学邓普天文与天体物理研究所）；Data Sciences Institute, University of Toronto（多伦多大学数据科学研究所）；School of Physics, University of New South Wales（新南威尔士大学物理学院）；Department of Physics, University of Surrey（萨里大学物理系）；Department of Astronomy & Astrophysics, University of Chicago（芝加哥大学天文与天体物理系）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙物理研究所）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天文研究所）；Institute of Astronomy, University of Cambridge（剑桥大学天文研究所）
MUSE-DARK IV. Comparing Dark Matter Densities to Star Formation Histories in 375 intermediate-z galaxies
Université Lyon 1, ENS de Lyon, CNRS, CRAL（里昂第一大学，巴黎高等师范学院里昂分校，法国国家科学研究中心，里昂银河系与天体物理实验室）；Leibniz-Institut für Astrophysik Potsdam (AIP)（波茨坦莱布尼茨天体物理研究所）；Univ. de Strasbourg, CNRS, Observatoire astronomique de Strasbourg（斯特拉斯堡大学，法国国家科学研究中心，斯特拉斯堡天文台）；Institute of Cosmology & Gravitation, University of Portsmouth（朴茨茅斯大学宇宙学与引力研究所）
We study the effects of dark matter self-interactions on the local dark matter distribution in selected Milky Way-like galaxies in the EAGLE hydrodynamical simulations. The simulations were run with two different self-interacting dark matter models, a constant and velocity-dependent self-interaction cross-section. We find that the local dark matter velocity distribution of the Milky Way-like halos in the simulations with dark matter self-interactions and baryons are generally similar to those extracted from cold collisionless dark matter simulations with baryons. In both cases, the local dark …
GHASP: an H$α$ kinematical survey of spiral galaxies - XI. Distribution of luminous and dark matter in spiral and irregular nearby galaxies using WISE photometry
我们提出了一个样本的质量分布的121个附近的星系与高质量的光学速度场和可用的红外$\it{WISE}$ 3.4 $μ$ m数据。与以前的研究相反，这个样本涵盖了所有的形态类型，并不偏向于晚型星系。这些星系是法布里-珀罗运动学$\it{GHASP}$调查的螺旋星系和不规则的附近星系的一部分。结合运动学数据的$\it{WISE}$表面亮度数据探测从老恒星人口的排放，我们推导出质量模型，使我们能够比较发光的暗物质晕质量分布在这些星系的光学区域。暗物质（DM）模型是利用等温核轮廓和Navarro-Frenk-White尖点轮廓建立的。我们允许重子盘的M/L变化或我们保持固定，恒星演化模型（WISE W $_1$ -W $_2$颜色）的约束，我们进行最佳拟合（BFM）和伪等温最大盘（MDM）模型。我们发现，MDM提供的M/L值比BFM高四倍，这表明平均而言，椎间盘成分往往是最大的。主要结果如下：（i）大多数星系的自转曲线更适合于核心而不是尖点轮廓;（ii）DM参数和发光物质组分参数之间的关系主要取决于形态类型。更准确地说，DM在星系内部的分布取决于星系是否有凸起。
